Journal of the History of Biology, Vol. 4, No. 2

Preformation and Pre-existence in the Seventeenth Century: A Brief Analysis PETER J. BOWLER Institute for the History and Philosophy of Science and Technology UniveTsity of ToTonto Toronto, Canada

INTRODUCTION The purpose of this paper is to analyze the various factors which contributed toward the development of what has often been called the "theory of preformation." The eighteenth-century version of this theory, popularized by Bonnet, Hailer, and others, centered upon the concept of emboitement, the belief that the generation of new organisms was nothing more than the expansion of miniatures which had existed since the first creation of the universe, stored up one generation within another. This first became popular toward the end of the seventeenth century, when many different factors combined to promote its development. Some of these factors have only an indirect relationship to emboitement itself, but have often been confused with it; the following discussion will attempt to distinguish the various positions supported by the embryologists of the late seventeenth century, and to assess their contributions to the growth of the theory which became so popular in the following century. The first step in the analysis must be a definition of the term "preformation" itself, but this is not a straightforward procedure. Most works in English on the history of embryology' have used the term to refer to any position involving a belief in the existence of a miniature organism at some time before conception. This very wide definition may easily generate confusion, because 1. E.g., F. J. Cole, Early Theories of Sexual Generation (London: Oxford University Press, 1930); Joseph Needham, A History of Embryology, 2nd ed. (New York: Abelard-Schuman, 1959); H. B. Adelmann, Marcello Malpighi and the Evolution of Embryology (Ithaca, N.Y.: Cornell University Press, 1966), and Elizabeth Gasking, Investigations into Generation 1651-1828 (London: Hutchinson, 1967). Journal of the History of Biology, vol. 4, no. 2 (Fall 1971), pp. 221-244.

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it admits emboitement as but one version of preformation, thereby encouraging the tendency to overemphasize the connection between emboitement itself and various positions which are not directly linked with that concept, although they are "preformationist" in this broad sense of the word. Roger2 has stressed the distinction between preformation and pre-existence, which helps to clarify the issue and will be adopted in the rest of this analysis. All theories based upon the belief that organisms have been in existence in the form of miniatures since the creation of the universe will be called pre-existence theories. It will thus be no longer correct to describe emboitement as part of the theory of preformation. The term "preformation" will be retained only for the belief that the miniature which grows into the full organism is actually formed within the body of the parent. The two terms must be clearly seen as referring to quite different concepts, related only by the common expectation that it should be possible to discover evidence in favor of the presence of a miniature before conception. The difference between their theoretical backgrounds means that this expectation represents the only possibility of a historical link between them. The distinction between the two concepts facilitates the analysis of this link and other important relationships, but it is not adequate to allow the construction of a complete picture of the complex process by which pre-existence became a central part of embryological thought. In the course of the following discussion it will thus be found necessary to superimpose several additional distinctions upon it. PREFORMATIONAND METAMORPHOSIS Both preformation and pre-existence are usually contrasted with epigenesis, which Harvey defined as the sequential production of the parts of the embryo. But for Harvey himself, the alternative to epigenesis was not preformation (pre-existence had not appeared on the scene by the time he wrote) but metamorphosis, in which all the parts appear simultaneously some time after conception.3 His original definition was meant to apply to the insects and lower animals, and allowed only for the sudden appearance of the full-sized organism, but there were other workers who believed that the higher animals were generated by a similar process in which a complete miniature organ2. Jacques Roger, Les Sciences de la vie dans la pens6e frangaise du XVIII. siecle (Paris: Armand Colin, 1963), p. 325. 3. The definitions of epigenesis and metamorphosis may be found in Harvey's De Generatione Animalium in The Works of William Harvey (New York: Johnson reprint, 1965), p. 334.

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Preformation and Pre-existence in the Seventeenth Century ism was formed at an early stage in the development of the fetus. For at least one of these workers,4 this process was also called metamorphosis, thereby providing a considerable extension of Harvey's definition. Since the belief itself was of considerable importance at the time, this use of the term will be adopted in the following discussion for the sake of simplification. The relationship between metamorphosis, preformation, and preexistence must be clearly understood if they are not to be confused with one another. At the theoretical level, any theory based on metamorphosis is as much opposed to pre-existence as one based on epigenesis. Indeed, in the eighteenth century, one of the leading opponents of emboitement was Buffon, whose theory has often been called epigenetic, but was specifically committed5 to the production of a miniature shortly after conception. Such a theory would be as completely falsified by an admission of the validity of epigenetic observations such as those of Harvey and Wolff as would Bonnet's emboitement. This suggests that, whatever their differences, metamorphosis, preformation, and preexistence have similar observational consequences, since each indicates that it should be possible to see a complete organism shortly after conception, although preformation and pre-existence also suggest that it may be seen even before that time. This similarity should not be allowed to disguise the essential difference between metamorphosis and pre-existence, but unfortunately the distinction between metamorphosis and preformation is not as clear owing to the confusion existing in some writings as to whether the miniature appears just before or just after conception. This latter problem is not too serious, since whatever the confusion in the minds of some speculators, the microscopists were generally better aware of the implications of their observations. For this reason, we should be very careful in our assessment of the importance of the link which these observations might provide between the older preformation theories and the rise of the emboitement concept. There are two groups of embryological observations that would serve to bridge such a gap. Those made before conception has occurred, if they indicate that a miniature organism exists, can be relevant only to preformation or preexistence. But the large number of observations of the growth of the embryo after fertilization, of which the most important are those of Malpighi upon the development of the chick, may be relevant to both metamorphosis and preformation. Some of 4. Dr. William Croone, whose work is discussed below. 5. See Buffon, Histoire naturelle, g6n&rale et particuli&re, (Paris, 1749) II, 292.

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these workers suggested that the whole organism, or, in Malpighi's case, the rudiments of all the important organs, appeared together shortly after conception. In the eighteenth century, such claims formed the most important evidence for pre-existence, since the occasional reports of the discovery of a miniature before conception, or in an unfertilized hen's egg, were always treated with a touch of skepticism. But in the seventeenth century, it was quite possible for this work to be inspired by and interpreted as support for metamorphosis, rather than preformation or preexistence. The early preformation theories may have had some effect, but their influence must be assessed along with that of metamorphosis and, in some cases, sheer over-enthusiasm in the use of the microscope. It was only as the emboitement theories gained popularity at the end of the century that such observations became generally interpreted as favorable to preexistence. Even before the microscope came into general use, disputes had arisen concerning the development of the fetus by metamorphosis and the relevance of observation to this problem. Harvey's observations in support of epigenesis appeared in his De Generatione Animalium in 1651. Ten years later, his interpretation was questioned by Anthony Everard, whose Novus et Genuinus Hominis et Brutique Animalis Exortus included an account of the development of the rabbit fetus. Like Harvey, Everard was strongly influenced by Aristotle.0 He could not have accepted preformation, since he believed that the male semen contributed only a spiritual element responsible for forming the fetus from material supplied by the mother. Nor did his observations support preformation; he agreed with Harvey that there was no sign of an embryo for some time after conception, and held that it crystallized out of a liquid when it finally made its appearance. His main point was that a complete miniature crystallized out at one point in time, because a dissection of the female rabbit nine days after coitus revealed that some chambers of the uterus already contained a fetus the size of a pinhead, whereas others did not. He did not use the word "metamorphosis," probably because he realized that his position did not correspond exactly to Harvey's definition, but his claim that the parts are delineated simultaneously represented a definite contradiction of Harvey's support for epigenesis. Strangely enough, the observations on the rabbit do not seem to have been the basis of his 6. For a description of the disputes over Aristotle's doctrines, and Everard's place within them, see Roger, Les Science de la vie, pp. 53-68 and 91-94. See also Adelmann, Marcello Malpighi, II, 765-769, and the translation from Everard's work, pp. 782-797.

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Preformation and Pre-existence in the Seventeenth Century criticism, since Everard admitted that he could not see all the organs within the fetus as it appeared and put forward what later became the standard argument of the supporters of emboitement that we should not rely upon the senses to reveal minute structures which may, by their very nature, be invisible. His opposition to epigenesis was based on theory rather than observation, probably deriving from a study of the Hippocratic corpus, whose doctrines Everard fused with his Aristotelian ideas, but a similar opposition to epigenesis seems to have motivated several of the workers who first applied the microscope to the study of embryology. Everard's opinions were taken up by Dr. William Croone, an early member of the Royal Society, who undertook a series of observations on the hen's egg in the hope of providing more conclusive evidence. His paper was read to the Society in 1672, just as Malpighi's observations were being published. Unlike Everard, Croone did use the term "metamorphosis" to describe the sudden formation of the embryo: I for my part, to tell the truth, was only too willing to see anything which could confirm my previously conceived opinion concerning the instantaneous generation of animals by means of metamorphosis (as the saying is). I had read, two years before, the contribution to this subject made by Anthony Everhard, a man of very great learning; and, to conceal nothing, it was from the conclusion which he adduced (page 75) from Harvey that I was for the first time given occasion to suspect that sooner or later something would be found in the egg which would give everyone a confident belief in the truth of this opinion.7 Croone's observations were performed on fertilized eggs, so there was no hint of preformation in them, and his claim was simply that the features of the chick could be seen before the egg was incubated. This does not, in fact, solve the problem of the development of the fetus in the egg before it is laid, but Croone was convinced that his observations supported metamorphosis. Cole suggests that his chick was merely a crumpled piece of membrane, in which the over-eager Croone saw the proof of the position he had derived from Everard. Croone's paper illustrates not only the influence of the idea of metamorphosis, but also the 7. Translated in F. J. Cole, "Dr. William Croone on Generation," in M. F. Ashley Montague, Studies and Essays in the History of Science and Learning Offered in Homage to George Sarton (New York: Schuman, 1944), p. 119.

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power of the newly discovered microscope to encourage the less skillful observer's imagination to run away with itself. It is difficult to assess the impact of the work of Everard and Croone. Since Croone's paper was not printed until 1757, in Birch's History of the Royal Society,8 he can have had no international influence, but there is evidence that his opinions did, at least, affect the manner in which the Royal Society interpreted the far more significant observations of Malpighi. There is no evidence that Malpighi himself was aware of Everard's book. Adelmann's study of the possible influences upon his thought'9 shows that he may have been affected by the work of Highmore, Gassendi, and Fabri who were, in effect, carrying on the tradition of the theories of Aromatari and others which are described as preformationist by Roger. But Malpighi generally preferred to depend upon observation rather than authority, and if these ideas influenced him in his belief that the rudiments of the whole fetus appear in the egg before it is incubated, they certainly did not predispose him toward preformationism. Adelmann points out that Malpighi's work does not support preformation,"' despite the common belief to the contrary. His observations were performed on fertilized eggs, starting before incubation, although some of the development he observed at the early stages may have been due to the fact that his eggs were left for some time before being opened. He argued only for the existence of rudiments of the important organs before incubation, a position closely resembling metamorphosis, although Malpighi also believed that the fetus underwent definite changes in the course of its development. When it is remembered that the spermatoza had not yet been discovered, there is one particular observation that strongly supports the claim that Malpighi was not a preformationist. This is his recognition of the fact that there is no structure comparable to the miniature embryo to be found within an unfertilized or subventaneous egg. He remarks that the corresponding part of such an egg "when torn open revealed no structure peculiar to and different from it." 11 It is significant that this observation, which clearly shows that Malpighi did not believe in the appearance of a miniature before fertilization, was noticed and commented upon by his contemporaries. This suggests that they were aware of the real 8. See Thomas Birch, History of the Royal Society of London, London, 1757 (New York: Johnson reprint, 1968), III, 30-40. 9. Adelmann, Marcello Malpighi, II, 901-910. 10. Ibid., pp. 885-886. 11. Ibid., p. 947, Adelmann's translation of Malpighi's De Formatione Pulli in Ovo of 1672.

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Preformation and Pre-existence in the Seventeenth Century implications of his work and did not believe him to be supporting a preformation theory. The account of the De Formatione Pulli in Ovo in the Royal Society's Philosophical Transactions of 1672 states that the structures observed were present before incubation, not before fecundation, adding that in subventaneous eggs "instead of such a formation, there is found nothing but an unformed globous ash-coloured body, like a mola."'12According to Birch, the Royal Society took both Malpighi and Croone to be supporting the same point of view.13 Whatever the influence of metamorphosis upon Malpighi's thoughts, it is quite probable that Croone ensured that, in England, at least, his work was taken as a contribution to the debate centered upon that concept. Even de Graaf's report of what was thought to be the mammalian ovum, and his opinions on the development of the organism from it, were tied in with the work of Malpighi and Croone,14and the Society also reported the observations of Kerkring, who claimed to be able to discern a human fetus, complete with skeleton, only a few days after conception.15 Their prudent notice of de Graaf's objections to such extravagant claims shows that they would not allow themselves to be carried away to this extent, even on the subject of metamorphosis, so it is not surprising that no mention of actual preformation was made in these reports. Interest in the metamorphosis concept declined with the introduction of the more extreme pre-existence theories, but for some time others besides the members of the Royal Society continued to appreciate the true significance of Malpighi's work. In the following twenty years, his observations were used by Peyer,'6 Borelli,17 and Garden'8 as evidence for the fact that a miniature does not exist within the unfertilized egg. Not until the eighteenth century did Malpighi acquire his reputation as a "preformationist," when embryologists such as Haller and Wolff interpreted him in this light.19 PREFORMATIONAND OBSERVATION Turning to the belief that a miniature fetus actually exists, 12. Philosophical Transactions of the Royal Society (Phil. Trans.) (New York: Johnson reprint, 1968), 7, no. 87 (1672), p. 5080. 13. See Birch, History of the Royal Society, III, 30. 14. Phil. Trans., 7, no. 82 (1672), pp. 4053-4054. 15. Ibid., no. 81 (1672), pp. 4018-4026. 16. In a letter to J. J. Harder in 1678, quoted in Adelmann, Marcello Malpighi, II, 919. 17. Borelli, De Motu Animalium (Leiden, 1710), pt. 2, p. 242. (lst ed. 1680-1). 18. Phil. Trans., 16, no. 192 (1691) p. 477. 19. See, for instance, Adelmann, Marcello Malpighi, II, 886, 893.

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and may even be seen, before conception, we find ourselves confronted with a much less rigorous attitude toward observation. A belief in the existence of such miniatures certainly gained some ground in the late seventeenth century and played a role in promoting the popularity of the emboitement theories, but no respectable microscopist ever gave his support to a clear confirmation of the belief. Most of the reports of preformed embryos were no more than vague suggestions, or in at least one case, a deliberate hoax. When these suggestions are made in association with arguments for pre-existence, as in Malebranche's early discussion of emboitement, it is evident that the new theories themselves governed the attitude of the writers to observation. But when such arguments do not appear, it seems improbable that the writer was affected by this extreme concept, and his motivation must be sought elsewhere. One possible influence is, of course, the early preformation theories. There are, however, several factors indicating that too much emphasis should not be placed on the ability of these theories to generate the belief in the existence of preformed miniatures which contributed to the rise of the pre-existence concept. The theories of Liceti, Parisiano, and Aromatari described by Roger 20 as typical examples of early preformationism held that the soul of the new organism is derived from those of its parents and is responsible for the construction of the fetus from material collected in the male and female semen. Similar opinions were put forward later in the century by Highmore, Fabri, and Gassendi,2' the latter holding that the soul itself was a material entity. The fact that these theories based themselves upon the mixing of two seminal fluids immediately reveals the gulf between them and the new belief in generation from eggs upon which much of the later support for preformation and pre-existence depended. Even within their own framework, their ability to suggest that it might be worthwhile searching for a miniature must have been rather limited, since it is difficult to see how both parents can contribute to an offspring that develops from a single miniature formed in the male or female semen before they are mixed. At least one early writer, Aromatari, believed only that plants are preformed within their seeds and did not extend this view to animals, arguing that the chick appears in the egg before incubation, not before fertilization. There must have been some tendency for these theories to 20. Roger, Les Sciences de la vie, pp. 126-131. 21. Sections of Gassendi's Syntagma Philosophicum and Fabri's Tractatus Duo are translated in Adelmann, Marcello Malpighi, pp. 804-810 and 911-914.

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Preformation and Pre-existence in the Seventeenth Century suggest actual preformation, since Sir Kenelm Digby found it necessary to attack such a view in his Two Treatises of 1644,22 but the lack of interest in the possibility shown by Harvey's 1651 work suggests that it was not too strong. In fact, the early works appear to have been completely forgotten,23 and there is little to suggest that the later writings of Gassendi and others had a direct preformationist influence upon those who were developing an attack upon one of their fundamental concepts. Two possible alternatives to the influence of the preformation theories suggest themselves. The first of these is simply an extreme form of the over-enthusiasm already noted in the microscopic study of the developing fetus. But far more important was the effect of the conflict between the new belief in generation from eggs and the old twin-semen theories, later replaced by the dispute as to whether the egg or the spermatozoon was the origin of the fetus. This conflict could generate a belief in the existence of visible miniatures in the supporters of ovism, as it was called, quite independently of any similar suggestion by the preformationist versions of the opposing twin-semen theories. The belief that the egg alone contained the potential to produce the fetus was partially supported by Harvey24and received a boost from the supposed discovery by de Graaf and others of the mammalian ovum. It did not, however, go unopposed25 and, although early ovists such as de Graaf and Malpighi did not accept preformation, it must have been obvious to the less careful supporters of the idea that the opposition could be silenced by the claim that a miniature fetus can be seen within the egg. The same argument 22. See Sir Kenelm Digby, Two Treatises, in the one of which the Nature of Bodies, in the other the Nature of Man's Soule, is looked into, in way of discovery of the Immortality of Reasonable Soules (London: 1644), pp. 272, 278. 23. A paper by Aromatari was reprinted in the Phil. Trans., 17-18, no. 211 (1694) pp. 150-152, with an introduction expressing surprise at finding these opinions put forward at such an early period. 24. See Harvey, Works, p. 370, where he compares the action of the male to that of the sun upon a developing fruit, and p. 421, where he suggests that a partially formed embryo may develop without the concurrence of the male. Harvey also realized that the male supplies some of the form of the offspring (e.g. Works, p. 363), but the ovist school tended to stress the former viewpoint. 25. In its report of Kerkring's support for ovism, Phil. Trans. followed the "French Philosophical Journals" in noting that his opinion "hath been very differently received, some appearing surprised at it, others rallying with it and many being induced thereby to make further inquiry into it." (Phil. Trans., 7, no. 81 [1672] p. 4019). In 1683, Phil. Trans. also published a paper (discussed below) which found it necessary to defend ovism against the old twin-semen theories. For the opposition to ovism in France, see Roger, Les Sciences de la vie, pp. 270-283.

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would apply to the animalculists who followed Leeuwenhoek in his belief that the animalcules of the male semen are the real origin of the fetus. This ability of ovism and animaculism to generate the desire to claim that a miniature can be seen within the egg or sperm should not be overlooked, even though it only rarely made itself apparent in complete isolation from the embottement concept. Examples of these alternative motivations may be found in the transactions of the Royal Society, where the influence of Malebranche's early arguments for pre-existence was less apparent than on the continent. Croone provides a good example of the over-enthusiasm that could affect some observers. Seven years after his paper reporting the discovery of a complete chick within an unincubated egg, he claimed that he had now seen a minute fetus in an egg which he knew to have been unfertilized. Such a claim amounts, in effect, to a substantiation of ovist preformation, but the account makes no mention of any effort on Croone's part to justify his position with arguments for ovism. He was almost certainly unaffected by the pre-existence concept, and the most likely explanation of his claim is a simple desire to make his observations seem all the more remarkable, although this time he apparently felt that it was not even necessary to use a microscope, since he was "desired to prosecute this experiment yet further, and to examine the cicatricula with a microscope, and shew it to the society." 26 The account dismisses the whole incident in one short paragraph, suggesting that the other members of the Society may have been a little skeptical of the claim, and no more was heard of the matter. The effects of ovism are illustrated by an anonymous paper printed in the Philosophical Transactions for 1683. The main argument of the paper is in favor of ovism, which is defended against the old twin-semen theories. There is certainly no trace of pre-existence in the arguments, but the belief that a miniature may be seen within the egg is introduced as a direct confirmation of the belief that the egg contains the potential to produce the whole new organism: And in both [animals and plants], the parts of the embryo are designed and drawn out, before the egg has been at all affected by the masculine seed, or the vegetable seed put into the womb of the earth. The figure of the plant may be seen in the larger seeds, and the miniature of a chick in the spot of the yolk.27 26. Birch, History of the Royal Society, III, 456. 27. Phil. Trans., 13, no. 147 (1683), p. 187.

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Preformation and Pre-existence in the Seventeenth Century The purpose of the claim appears clear, but it introduces two confusing elements which are common to almost all such accounts, whether influenced by the pre-existence theories or not. The first of these is the lack of precision of the report that a chick may be seen within the egg. The statement is obviously meant to imply that this is the case with an unfertilized egg, but it does not specify that, in order to substantiate its claim, the eggs used for observation must be known to be infertile. A reader might easily gain the impression that observations of the type provided by Malpighi may be taken as supporting preformation. Many were aware that this was not the case, and that without further substantiation that would have actually to contradict Malpighi, such reports were worthless, but it is clear that in such vague accounts we have the origins of the process by which Malpighi became known as a supporter of either preformation or pre-existence. The other confusion brought out by this paper concerns the connection between the structure of vegetable seeds and the question of preformation within the egg. In the absence of a welldeveloped theory of the sexuality of plants, the seed before it was put into the earth could be seen as analogous to the egg before fertilization. It was well known that the structure of the leaves could be distinguished in some seeds, thus providing apparently direct support for preformation or pre-existence. The later recognition of the true nature of plant reproduction revealed that this analogy was not valid because the seed was already fertilized before it was put into the ground. A new connection between plant and animal reproduction was forged, which in turn gave rise to a dispute over the basis of vegetable generation between the ovulists and pollenists, analogous to that between the ovists and animalculist.28 The pre-existence concept also entered into this dispute, but no longer could the seed be regarded as unfertilized, so that the existence of a plant within the seed could be seen to bear only the same relationship to vegetable emboitement as Malpighi's observations did to the animal version, both providing only indirect support for the pre-existence theories. By introducing these two elements of confusion, the 1683 paper attempts to show that observation supports the preformationist interpretation of ovism. No mechanism by which the miniature might be formed is described, suggesting that the early preformation theories did not contribute toward the writer's 28. Described in P. C. Ritterbush, Overtures to Biology (New Haven, Yale University Press, 1964), pp. 88-98.

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ideas. The paper may be called "preformationist" (in the strict sense of the term) only by virtue of the fact that, in the absence of any reference to pre-existence, the writer must be presumed to have adopted the alternative belief of Malpighi and de Graaf that the egg, and hence the miniature he supposes it to contain, is generated within the mother. It may be noted that the paper puts forward no arguments against the animalculist position supported by Leeuwenhoek since the discovery of the animalcules of the male semen in 1677. Although it published his letters, the Royal Society adopted a generally skeptical attitude to Leeuwenhoek's ideas, but it could not prevent animalculism emerging as the principal opponent of ovism as the twin-semen theories lost popularity. Eventually, animalculism became associated with emboitement, but Leeuwenhoek himself remained largely unaffected by the latter concept. Nevertheless, he did become aware of the possibility of substantiating his belief that the spermatozoon contained the potential to produce the fetus by discovering a miniature within it. He did not openly support such a claim, and often expressed suspicion concerning it, but there are passages in his letters clearly indicating that he was partially affected by the same motivation as that governing the author of the 1683 paper in his suggestion that a miniature can be seen within the egg. Leeuwenhoek's first report of the animacules29 already suggested that the semen is the principal agent in generation. At this early stage he was not interested in the animacules themselves but in certain particles occurring in the thicker parts of the semen in which he thought he could discern a resemblance to the various parts of the human body. He may have been influenced by the pangenesis of some of the earlier theories in which the fetus is built up from representative particles derived from the parts of the parents' bodies, but it is not clear whether Leeuwenhoek was inspired by these ideas, or merely allowed himself to be carried away by his enthusiasm for his discovery. Whatever its source, there was already a somewhat unusual element of preformationism present in his thought ready to emerge in later discussions where he fixes upon the animalcules themselves as the origin of the whole fetus. Thus in a letter of 1685 he allowed himself to speculate on the possibility that the animalcule contains a miniature, but immediately contradicted this and insisted that anyone who had interpreted his reports 29. Written in November 1677 but not published in Phil. Trans. until no. 142 for December, January, and February 1678 (vol. 11-12, pp. 10401043) accompanied by a rejection of Leeuwenhoek's ideas and part of his reply reaffirming his opposition to ovism.

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Preformation and Pre-existence in the Seventeenth Century to mean that the animalcules contained children was mistaken. The kernel of an apple is not a tree, and it is "no less improper to say, that the worms in mens' seed are children, tho' children come from them." 30 Leeuwenhoek was certainly convinced that the spermatozoon could produce a child, and was obviously tempted by the possibility that it might actually contain a miniature, but his own inability to discern such a structure seems to have prevented him from openly supporting such a claim. He does not seem to have reacted to Hartsoeker's famous drawing, published in 1694, of the manikin which he supposed lay within the sperm, but in 1699 he was forced to take note of the claims put forward under the name of Dalenpatius.31 With his reputation as a microscopist at stake, Leeuwenhoek completely rejected the possibility of observing structures such as those represented in the illustrations accompanying this claim. His own position, however, is again somewhat ambiguous: I put this down as a certain truth, that the shape of a human body is included in an animal of the masculine seed, but that a man's reason shall dive or penetrate into this mistery so far, that in the anatomising of one of these animals of the masculine seed, we should be able to see or discover, the intire shape of a human body, I cannot comprehend.32 Leeuwenhoek was aware of the emboitement concept, but many of his own speculations were incompatible with it, and it does not appear to have been the driving force behind his conviction that a miniature is "included" within the animalcule.:3 His support for animalculism was the real motivation, with his own observations still preventing him from regarding the enclosed fetus as a visible miniature. It now appears that, of the important microscopists of the late seventeenth century, neither Malighi nor Leeuwenhoek was influenced by the pre-existence theories, nor did their observations confirm such theories. Of those workers who accepted pre-existence and may have been prompted by this to argue that a miniature can be seen within the egg or sperm, only Swammerdam would have had the reputation to ensure that a report 30. Phil. Trans., 15, no. 174 (1685), p. 1133. 31. These "observations" were a hoax, perpetrated by de Plantade and published in J. Bernard's Nouvelles de la republique des lettres (Amsterdam, 1699). 32. Phil. Trans., 21, no. 255 (1699), p. 306. 33. At one point, Leeuwenhoek notes the possibility that the animalcules are "all descending from the first created man" (ibid., p. 271) but then goes on to suggest that they have two sexes and reproduce themselves.

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of such an observation would be taken seriously. But although Swammerdam is usually regarded as a founder of the "preformation" theory, he did not make this type of observation, and his contemporaries usually realized that his work was not relevant to the topic. His main interest lay in the study of the later stages of development, especially in insects, which have no relevance to either preformation or pre-existence. This fact should not be neglected in any study of either his observations or the brief speculations that entitle him to be classed as a contributor to the development of emboitement. Since this indicates that neither his observations nor his speculations were sufficiently definite to substantiate the belief that Swammerdam was committed to generation from miniatures, his contribution to the development of emboitement must be assessed with some care. There are two areas in which Swammerdam's observations have been regarded as relevant to this topic: his accounts of the development of insects first given in the Historia Insectorium Generalis of 1669, and a brief reference to the frog's egg found in the Miraculum Naturae of 1672. A sentence sometimes quoted from the eighteenth-century publication of the Book of Nature concerning the chick can be shown to be the result of a faulty translation into English.34 In the work on insects, Swammerdam was always dealing with fertilized eggs and was really concerned with exploring the later development of, for instance, the butterfly within the chrysalis. His demonstration of the existence of the complete insect some time before it was meant to appear from the chrysalis may have been used as evidence by some later supporters of embottement, but is in fact quite irrelevant to the real issue. Swammerdam even believed that the parts of the body 34. The English translation of Swammedam's Biblia Naturae (originally published by Boerhaave in 1737) contains the following sentence: "Nor, indeed can it be said that there happens any change on this occasion, than what is observed in chickens, from eggs which are not transformed into cocks or hens, but grow to be such by the expansion of parts already formed" (Swammerdam, The Book of Nature, or the History of Insects, trans. Thomas Flloyd, revised ed. lLondon,17581, p. 3). The original Dutch reads: "Synde dese verandering daar en boven niet anders als die van een Kuyken, het welke niet verandert in een hoen, maar aagreidende in leedematen soo wort het een hoen." (Swammerdam, Historia Insectorum Generalis, ofte Algemeene Verhandeling van de Bloedenloose Dierkens [Utrecht, 1669], p. 9). This may be translated literally as: "The above changes are nothing else than those of a chick, which is not changed into a hen, but becomes a hen by the growing of its parts." The substitution of "egg" for "chick" completely alters the sense of the passage, in which Swammerdam merely wished to suggest that an insect actually grows within its chrysalis, and is not suddenly formed in its final bulk. I am indebted to Prof. Mary P. Winsor of the University of Toronto for the above literal translation, and also for that in note 41.

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Preformation and Pre-existence in the Seventeenth Century appeared one by one; he was strongly opposed to the form of metamorphosis supported by Harvey and continually emphasized the use of the term "epigenesis" to describe insect growth. Concerning the frog, Swammerdam merely remarks that the black spot in the egg is "the frog itself complete in all its parts." 35 He certainly believed that the egg contained the potential to produce the frog, but that he did not intend his statement to mean that he had observed a miniature within it is clear from his more detailed discussion of the frog's development, published posthumously in 1737, which contained nothing compatible with such an observation. Whatever Swammerdam's actual meaning, the remark concerning the frog could certainly have been taken to indicate support for the pre-existence of miniatures. This was not, however, the general reaction to his observations. The account of his 1669 work in the Philosophical Transactions noted his brief speculations but concerned itself mainly with the observations, quite properly regarding them as a contribution to our knowledge of the various ways in which insects develop.36 The account of the 1672 work makes no mention of pre-existence,

nor does it mention the remark about the frog's

egg.37

The

observations certainly seem to have encouraged Malebranche, who referred to the works of both Swammerdam and Malpighi in his proposal of the emboitement theory in 1674, but he gave no details and does not seem to have shared the awareness of many of his contemporaries that a closer study of these works revealed that they were incompatible with pre-existence. The fact that Swammerdam almost certainly derived his own speculations from Malebranche indicates that the development of the latter's thoughts was not dependent upon these observations. Malebranche's attitude to the work of Swammerdam and Malpighi illustrates the fact that an acceptance of the philosophical background to emboitement generally preceded and was itself the cause of any attempt to interpret the observations as favorable to this type of theory. The pre-existence theories inspired no microscopic studies of lasting value in this period, nor were the theories themselves created in response to specific suggestions derived from observation. This would imply that the importance of the link that these observations at first appear to provide between the older preformation theories and the rise of 35. "ipsum ranuculum omnibus partibus absolutum" (Swammerdam, Miraculum Naturae, sive Uteri Muliebris Fabrica [Leiden, 16721, p. 21). 36. Phil. Trans., 5-6, no. 64 (1670), pp. 2078-2080. 37. Ibid., 7-8, no. 84 (1672) pp. 4098-5001.

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emboitement should not be overemphasized. Not only was the influence of the earlier theories upon the microscopists very limited, but the influence cannot be considered as having been passed on directly to the pre-existence theories. The belief that generation is nothing more than the expansion of pre-existing miniatures was inspired more by the discovery of the whole new world of microscopic objects (along with other more important factors) than by any specifically embryological observations. The claim that these miniatures can actually be seen arose out of the unwillingness of some of the workers who were more concerned with theoretical and philosophical problems to examine the relationship between their ideas and the available observations, an unwillingness that allowed them to speak vaguely of chicks and frogs being seen within the egg without specifying any real details. It has been noted that both ovism and emboitement could create this attitude, but whereas for the ovist the vague references to observations were no more than a convenient way of attempting to establish the importance of the egg, the latter concept was committed to the existence of miniatures whether they could be seen or not. The tendency to reinterpret microscopic discoveries encouraged by emboitement was but one aspect of a far-reaching change in ideas on the nature of generation. THE PRE-EXISTENCETHEORIES The chief motivation behind the construction of these theories was a conviction that the physical universe could not, of itself, be responsible for the generation of living organisms. Roger notes that the recognition of this problem derived partly from a revival of interest in the thought of St. Augustine,38 which also provided a solution by suggesting that, in effect, all organisms have been in existence since the creation of the universe and are themselves the direct result of a divine creation. This view was strongly supported by the mechanical philosophy introduced into biology by Descartes. The biologists subscribing to this idea could no longer accept a special vital or creative force as responsible for the formation of a new organism from its constituent materials. In the eighteenth century, matter was itself endowed with the ability to organize itself, but the more limited materialism of the seventeenth century could not explain how an animal, as a mere machine, could be responsible for the generation of other organisms approximately in its own likeness. Descartes himself 38. Roger, Les Sciences de la vie, pp. 332, 343.

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Preformation and Pre-existence in the Seventeenth Century had been able to break this conceptual barrier and imagine a machine to be capable of generation; the majority of the preexistence theories went to the opposite extreme of holding that the appearance of a new animal could be the result of nothing more than an increase in size, thus requiring the existence of physical miniatures originally created by God. This latter extreme includes the emboitement theories which became so popular with the opponents of eighteenth-century materialism, but we must note the existence of a third possibility, intermediate between the two extremes, which seems to have had some influence in the seventeenth century. Those who were affected by the mechanical philosophy, yet had an appreciation of the real meaning of the microscopic discoveries, could imagine generation occurring by means of a pre-existent design, in the form of a material system "programmed" to develop into a living organism. This position is quite compatible with observations illustrating the epigenetic growth of the fetus, and is thus the most likely explanation of Swammerdam's somewhat confused writings, but it did not achieve great popularity. The majority of thinkers preferred to adopt the more straightforward explanation provided by complete emboitement, despite the misinterpretation of the new discoveries required by this decision. Swammerdam's main concern in his work on the generation of insects was to oppose the old beliefs in metamorphosis and spontaneous generation. His opposition arose largely out of his belief that these processes would allow chance to operate in generation, whereas his own inclination was very much toward a view of nature as completely governed by law. He had read Descartes with enthusiasm and accepted the mechanical interpretation of life, although he never attempted to give mechanical models for biological processes in the manner of Descartes and Borelli. It has already been argued that Swammerdam's insistence on "epigenesis" in the descriptions of his observations is incompatible with the belief that generation is nothing more than the expansion of a miniature. He certainly believed that, in order to preserve a strict determinism throughout its growth, the organism must develop from a fixed design, which he fixed within the female egg once that body was supposedly discovered in the mammals in 1672. This, and the strong religious element in his thought, probably accounts for the ease with which he was influenced by Malebranche's suggestion that all organisms have existed since the creation of the world.39 In his work on insects, 39. In his Miraculum Naturae, Swammerdam merely said that these ideas were suggested to him by a "most learned man." According to Cole

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this influence emerges in two religious arguments. In the first, Swammerdam explains that the rejection of chance in generation can explain how Levi could be credited with paying tithes to Melchisedech when it was really Levi's great grandfather Abraham who paid the tithes before Levi's birth. In the second, he suggests that the doctrine of original sin can be explained if all living creatures were enclosed within the loins of their first fathers. In the Miraculum Naturae of 1672, he adapts these arguments to ovism by claiming that all men develop from eggs once enclosed within Eve, adding that once the eggs are used up, the human race will die out.40 It is evident that Swammerdam was fully aware of the pre-existence concept, but it would be difficult to reconcile the belief that he became committed to the complete emboitement theory with his own insistence on the epigenetic development of insects as a means of eliminating the operations of chance from nature. This would imply that he neglected his own work in order to adopt a belief which he obviously found interesting, but which he never expressed as anything more than a brief speculation. It is more probable that he merely saw in Malebranche's thought an interesting possibility that tied in with his own belief in the determinism of nature, and that he was no more committed to regarding the pre-existing design as an actual miniature than Malpighi, who, although unaffected by the pre-existence concept, became just as much convinced of the basic ovist belief in the existence of a design within the egg. Swammerdam is often thought to have held that there is no real generation in nature, a view which would connect him with the emboitement theory in which there is no "generation" since the complete organism has always existed as a miniature. But the original Dutch statement on this point is ambiguous, and his real meaning was more likely to have been that there is no generation by chance, rather than no generation at all.41 The (Early Theories of Sexual Generation, pp. 42-43), he later revealed that this was Malebranche. This latter assertion is questioned in A. Schierbeek, Jan Swammerdam, His Life and Works (Amsterdam: Swets & Zeitlinger, 1967), but the explanation itself is generally accepted. 40.

Swammerdam,

Miraculum

Naturae,

pp. 21-22.

41. Swammerdam's original Dutch reads: "Ende op datwe ons gevoelen daar van, in een of tween woorden, seggen: soo is't dat ons dunkt daar gansch geen Teeling in de geheele natuur te weesen, ende niet als een voorteeling, ofte aangroeing van deelen, waar in het alderminste geval geen toegank heeft, daar in ooit te bemerken" (Historia Insectorum Generalis, p. 51). This may be translated literally as: "And to express our feelings on this in one or two words, it appears to us: that there is absolutely no generation in the whole of nature, and not as generation,

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Preformation and Pre-existence in the Seventeenth Century French translation of 1682 adopted the former meaning, rendering the sentence as: "Nous disons qu'il ne se fait dans toute la nature aucune generation par accident, mais par propagation et par un accroisement de parties, oiule hazard n'a pas la moindre part."42 The account of the original work in the Philosophical Transactions for 1669 takes the opposite view of this passage, noting that "there is no generation in nature,"43 but this was the only reference to the pre-existence issue in the account, the religious arguments were not noted, and the whole issue was avoided in the account of Swammerdam's 1672 book. These latter points have already been noted as evidence for the fact that Swammerdam was not always taken as a founder of the theory of generation from pre-existing miniatures. The coincidence between Swammerdam's speculations and the nature of his arguments against metamorphosis did, however, convince some of his contemporaries that he supported generation from miniatures. Strangely enough, one of these was J. C. Peyer, who later adopted pre-existence in a manner which suggests that he also believed only in the pre-existence of designs rather than miniatures. In 1678, Peyer rejected what he took to be Swammerdam's theory as being incompatible with Malpighi's observations.44 But he was strongly influenced by the mechanical philosophy, and in his Merycologia, sive de Ruminantibus et Ruminatione Commentariae of 1685 he proposed that the Idea Realis of each organism must have been originally created by or growing of parts, where chance has no access whatsoever, which has ever been noticed." Compare the ambiguity of this with Flloyd's translation, which definitely suggests that there is no generation: "That we may give our opinion on this head in a few words, it seems very probable, that in the whole nature of things there is no generation that can be properly so called, nor can any thing else be observed in this process, than the continuation, as were of the generation already preformed, or an increase of, or addition to the limbs, which totally excludes the doctrine of fortuitous propagation" (Book of Nature, p. 16). If we accept the alternative view of Swammerdams meaning, then both his opposition to generation by chance and his reference to the "growing of parts" fit in with his overall purpose, which was to destroy the common belief that insects develop by metamorphosis, in the sense of that word as defined by Harvey. 42. Swammerdam, Histoire g6n&rale des insectes (Utrecht, 1682), p. 47. 43. Phil. Trans., 5-6, no. 64 (1670), p. 2079. 44. In a letter to J. J. Harder in 1678, quoted in Adelmann, Marcello Malpighi, II, 919. The views expressed in this letter are incompatible with Peyer's later ideas, but his attitude toward the microscopic discoveries need not have changed if his later pre-existent entities were not thought of as miniatures. Peyer could then have continued to accept, as he did in the letter, that Malpighi's observations of the unfertilized egg falsified Swammerdam's supposed claim.

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God and stored within the females of the first generation. The Idea was certainly a material entity, but Peyer's earlier reaction to Swammerdam suggests that he did not regard it as an actual miniature. His book had little influence,45 however, and John Ray, the only person who seems to have taken note of his ideas, interpreted them as part of the normal emboitement theory.46 Ray's reaction illustrates how the greater simplicity of the belief in generation by the expansion of miniatures enabled it to become by far the more powerful version of pre-existence amongst those whose knowledge of the new microscopic discoveries was not detailed enough to force them into accepting the much less straightforward belief in the pre-existence of designs. The theory of complete pre-existence was developed in three distinct ways: panspermism, in which the pre-existing miniatures float in the air, ovist emboitement in which they are enclosed one within the other inside the egg, and animalculist emboitement in which they are enclosed within the sperm. The first indications of the idea occur in the speculations that Swammerdam derived from Malebranche and published in his book of 1669. At that time the exact site of the pre-existing entity was not discussed, but in 1672 Swammerdam placed it in the egg and then in 1674 Malebranche himself described the ovist version of emboitement in his Recherche da la ve'rite. In the section devoted to the errors of the senses, Malebranche introduces the possibility of the existence of objects so minute that they cannot be detected. He then mentions the structure of the leaves which can be seen in the seeds of some plants and suggests that this implies that there might be an infinite series of miniatures enclosed one within the other: 11 ne parolt pas meme deraisonnable de penser, qu'il y a des arbres infinis dans un seul germe; puisqu'il ne contient pas seulement l'arbre dont il est la semence, mais aussi un tresgrand nombre d'autre semences, qui peuvent toutes renfermer dans elles memes de nouveaux arbres, & de nouvelles semences 45. Peyer's book was mainly concerned with ruminant animals, and his discussion of generation was not even mentioned in the account given in Phil. Trans. 15, no. 177 (1685), p. 1246. 46. Ray spoke of the eggs containing "animalcules." See John Ray, Three Physico-Theological Discourses, 3rd ed. (London, 1713), p. 50. He speaks quite favorably of ovist emboitement, expressing opinions differing considerably from those put forward in his Wisdom of God, where he had argued for a "plastick virtue" as the agent responsible for generation and poured scorn on the ability of the mechanical philosophy to deal with that problem.

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Preformation and Pre-existence in the Seventeenth Century d'arbres; lesquelles conserveront peut-etre encore dans une petitesse incomprehensible, d'autre arbres, & d'autres semences aussi fecondes que les premieres, & ainsi 'al'infini.47 Malebranche then refers to Malpighi and Swammerdam to support the belief that the eggs of the hen and the frog can also be seen to contain miniatures. We have already noted that this implies that he had not studied closely the revelance of this work to his idea, and his whole discussion reveals that he was more inspired by an awareness of the whole new world of minute objects revealed by the microscope than by actual embryological observations. Malebranche's idea also developed from his rejection of the possibility that the material world could create a new organism, but he does not discuss the argument derived from the mechanical philosophy which eventually became one of the chief motivations behind the rise of the pre-existence theories. This argument was to a large extent the contribution of Claude Perrault, who discussed it in his Mecchanique des animaux, read to the Academie des Sciences in 1679 and published as part of his Essais de physique. Perrault was the founder of the panspermist version of pre-existence, putting this forward as a solution to the problem which he saw in the apparent inability of the animal-machine doctrine to cope with generation. His pre-existing miniatures were not enclosed within one another, they floated freely, until absorbed by a parent organism which supplied the conditions necessary for development. On con,coit plus facilement, 'a la faveur de la divisibilite infinie de la matiere, que de petits animaux, trop petits pour se laisser appercevoir aux plus fins microscopes, deja organises, due moins quant 'a la disposition de leurs parties principales, & cependant sans vie, incapables, 'a cause de leur extreme petitesse, de toutes les fonctions qui appartiennent aux animaux, n'attendent que quelque liqueur asses subtile, qui s'insinue dans leurs pores, & commence a etendre leur volume; apres quoi le developpement continue, & se perfectionne toujours." 48

Perrault's remark that the miniatures would be too small to be seen by the microscope shows how insignificant was the part played by microscopic observation in the development of the pre-existence theories. The main inspiration was philosophical, and the importance of Perrault's work does not lie in any wide 47. Malebranche, Recherche de la vrit6, in Oeuvres completes, ed. Genevieve Rodis-Lewis (Paris: Libraire Philosophique J. Vrin, 1962), I, 82. 48. Histoire de l'Academie Royale des Sciences, 1666-99, I, 280.

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acceptance of panspermism, but in his clear statement of the problems arising from the mechanical philosophy. By bringing about this connection between the mechanical philosophy and pre-existence, Perrault's work had a much greater influence on the study of generation than did that of Borelli, the other major exponent of the mechanical view of living organisms, who rejected both preformation and pre-existence and followed Descartes in putting forward a rather unconvincing mechanical account of epigenetic development.49 Animalculist emboitement was the last of the pre-existence theories to appear, mainly because Leeuwenhoek did not develop his ideas in this direction, and few others followed him in his belief that the animalcule is the origin of the fetus. It is significant that Dr. George Garden of Aberdeen, who first associated animalculism with embottement, referred to Perrault as the source of his ideas, and was deeply impressed by his account of the limitations of the animal-machine doctrine: And indeed all the laws of motion which are yet discovered, can give but a very lame account of the forming of a plant or animal. We see how wretchedly Des Cartes came off when he began to apply them to this subject; they are form'd by laws yet unknown to mankind, and it seems most probable that the stamina of all the plants and animals that have been, or ever shall be in the world, have been formed ab origine mundi by the Almighty Creator within the first of each respective kind.50 Garden paid more attention to the work of Malpighi than did the followers of the ovist theory, using his observations of the unfertilized egg to support his claim that the miniature could come only from the animalcule. Presumably Garden found this a more likely alternative than Perrault's invisible organisms, but he made no attempt to claim that a miniature can actually be seen within the sperm. He did, however, adopt the increasingly popular view that Swammerdam's observations of insect development could be taken as indirectly favorable to pre-existence, since the demonstration that the insect may exist within the chrysalis and yet be very difficult to see suggests that the same may apply to the sperm. But he did not regard Swammerdam as having argued for the existence of a miniature within the 49. Borelli suggested that an oscillating motion set up in the fertilized egg produced the fetus by means of a process comparable to the working of a clock; see Borelli, De Motu Animalium, pt. 2, p. 245. 50. Dr. George Garden, "A Discourse concerning the Modern Theory of Generation," Phil. TTans., 16, no. 192 (1691), pp. 476-477.

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Preformation and Pre-existence in the Seventeenth Century unfertilized egg, and as far as assessing the direct relevance of observation for pre-existence, Garden emerges as a careful thinker, whose attitude to Malpighi suggests that the latter's work should be regarded as an important factor in the development of animalculist emboitement. Garden was aware of the importance attached to the female egg by many workers, suggesting that the animalcule could only develop within that body, an idea also taken up by Hartsoeker. This was, perhaps, the closest that a pre-existence theory could come to recognizing the contribution of both sexes to the formation of the offspring, but the animalcules were often regarded with some suspicion, and it was in its ovist version that the pre-existence theory became best known in the eighteenth century. CONCLUSION It is beyond the scope of this paper to describe in detail the rise to popularity of the emboitement theories during the last decades of the seventeenth century.5l Eventually the theories did gain great influence, but some points emerging from the above discussion indicate that the rise to popularity was not, perhaps, quite as rapid as has sometimes been assumed.52 Although the earlier preformation theories were sometimes regarded as the ancestors of the later ideas,53 there was little intellectual continuity between the two movements, based as they were upon such divergent motivations. Nor can the preformation theories be regarded as the origin of the belief that a miniature can actually be seen within the egg, since the existence of metamorphosis as a perfectly valid alternative to epigenesis meant that the work of Malpighi and others, usually described as "preformationist," was not always taken in this latter sense at the time it was published. The pre-existence theories developed in response to particular philosophical problems, and were themselves responsible for the reinterpretation of the observations. In France, the thoughts of Malebranche and Perrault were probably already exerting influence before their written support for pre-existence appeared, but elsewhere the idea was not taken up so rapidly, and ovism, for instance, could develop without associating itself with emboitement. Malpighi 51. The best account of this may be found in Roger, Les Sciences de la vie, pp. 334-354. 52. Cole, for instance, suggests that the theory was widely accepted after 1674; see Cole, Early Theories of Sexual Generation, p. 53. 53. The introduction to the reprint of Aromatari's paper in Phil. Trans. (17-18, no. 211 (1694), pp. 150) seems to regard his ideas as similar to those of its own time.

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always seems to have remained opposed to pre-existence,54 but by the last decade of the century, the idea had become sufficiently powerful to influence Ray and Garden in Britain, and was receiving support from as influential a thinker as Leibniz.55 But Garden and Hartsoeker were responsible for dividing emboitement between two schools, just as the concept itself was becoming popular. The work of both Malpighi and Leeuwenhoek served as the basis of the animalculist version, illustrating how the microscopic discoveries served as much to disrupt the intellectual development of the emboitement concept as they did to promote it. 54. See Adelmann, Marcello Malpighi, II, 886. 55. Sometime after 1672, Leibriz had held that the "souls are already in the human egg, before conception": see Yvon Belavel, La Pensee de Leibniz (Paris: Bordas, 1952), p. 105. Eventually he accepted actual emboitement, but for some time his published work gives no indication of which version he supported. In his "New System of the Nature and Communication of Substances, as well as the Union between the Soul and the Body" of 1695, he mentioned emboitement, citing Malebranche, Regis, and Hartsoeker as holding opinions similar to his own; see Leibniz, Philosophical Papers and Letters, trans. L. E. Loemker (University of Chicago Press, 1956). Of these, two are ovists, one an animalculist. In 1705 he was still undecided (ibid., II, 958-959), but clearly preferred the animalculist version in the Principles of Nature and of Grace of 1715 (ibid., II, 1037). The earlier uncertainty is typical of the lack of precision of many early versions of emboitement, formulated to solve metaphysical rather than biological problems.

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The Iatromechanical Background of Lagrange'sTheory of Animal Heat DIANA LONG HALL Boston University Boston, Massachusetts

Why did the Italian mathematician Joseph Louis de Lagrange become involved in the controversy over the site of animal heat production in the 1790s? Contemporaries knew Lagrange as a pure mathematician who considered such excursions into physics and physiology a waste of time.' We have known that Lagrange read medical books as a diversion and out of concern for his own health,2 but until now there has been no evidence that he wasted his time in experiments or discussions of physiological problems related to respiration before his rejection, about 1791, of the theory of Lavoisier and Laplace that respiration is a slow combustion in the lungs. Lagrange reflected that if all the heat which is distributed in the animal economy were set free in the lungs, the temperature of the lungs would necessarily be raised so much that one would have reason to fear they would be destroyed, and that moreover were the temperature of the lungs so much higher than that of the other parts, this fact could scarcely have escaped observation. Lagrange proposed instead that oxygen enters the blood in the lungs and gradually releases its heat as it reacts with the carbon and hydrogen in the circulating blood. The carbon dioxide and water formed by these reactions are released in the lungs.3 I have found evidence that the roots of Lagrange's physiologi1. Oeuvres de Lagrange, ed. J. A. Serrat (Paris, 1892), XIII, 368; letter from Lagrange to d'Alembert, 21 September 1781. 2. J. J. Virey, Precis historique sur la vie et la mort de Joseph-Louis Lagrange (Paris, 1813), 6; Maurice, "Lagrange," Biographie Universelle, 22: 533. 3. Lagrange's theory was reported by Jean Hassenfratz, "M6moire sur la combinaison de l'oxigene avec le carbone et l'hydrogene du sang, et sur la dissolution de l'oxigene dans le sang, et sur la maniere dont le calorique se degage," Ann. chim., 9 (1791), 266-67. Journal of the History of Biology, vol. 1, no. 2, pp. 245-248.

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cal interest and theory lie in Turin, where Lagrange was born in 1736, studied physics under Beccaria in the early 1750s, and taught at the Royal Artillery School from 1755 until his departure for Berlin in 1766.4 In Beccaria's laboratory he met G. F. Cigna, Beccaria's nephew, who was taking a degree in medicine. According to Vassalli-Eandi: 5 These two excellent young men did not delay in studying together. Their common love of exact science so gripped their minds that although they later went into different careers they continued to meet almost daily to discuss their studies and take turns at some experiments. The Comte de Saluces, a student at the Artillery interested in physics and chemistry, joined the discussion in Beccaria's laboratory. The three young men formed the Turin Philosophical Society and published the Miscellanea Taurinensis. The first (1759) volume of this journal opens with a summary by Cigna of the joint research of the three young men: "De Belliniano problemate, seu de ovorum elixatorum cicatricula" (3-7), "De varia barometrorum diversae diametri altitudine" (7-15), "De corrigendis barometrorum erroribus ex calore, et frigore natis" (15-21), and "De caussa extinctionis flammae in clauso aere" (22-51). Lagrange's role in all these studies was that of the cautious and ingenious physicist whose thought experiments produced such good results that Cigna thought they must have been real, not imagined.6 In the last paper Cigna, Saluces, and Lagrange proposed to test all current hypotheses concerning the vital physical property of the air by experiments on combustion in enclosed air. To this end they built a "machine," a lantern connected to an airpump, with which they showed that one could not renew vitiated air by recirculation, salt filters, or cooling.7 In their conclusion, Cigna, Lagrange, and Saluces speculated on the applicability of their results to air vitiated by respiration, a discussion Cigna pursued in his later papers on respiration.8 Lagrange's later theory of respiration made no reference to the 4. George Sarton, "Lagrange's Personality (1736-1813)," Proc. Amer. Phil. Soc., 88 (1944), 457-460. 5. A. Vassalli-Eandi, "Memorie istoriche intorno alla vita ed agli studi di Gianfrancesco Cigna," Misc. Taur., 26 (1822), xv. 6. [Cigna et all, "De varia barometrorum . . . ," Misc., Taur; 1 (1759), 9. One wonders why this sentence was omitted from the translation of the article in Rozier's Journal 2 (1772), 465. 7. [Cigna et all, "De caussa extinctionis flammae ...," Misc. Taur., 1 (1759), 24-42. 8. Ibid., 47-50; Cigna, "De caussa extinctionis flammae et animalium in acre interclusorum," Misc. Taur., 2 (1760-61), 168-203, and "De respira-

246

Lagrange's Theory of Animal Heat pneumatic theories tested by the Turin group; his chemical theory of the air and its combination with carbon and hydrogen came from Lavoisier. I suggest, however, that there is a connection between his argument over the site of heat production and another line of research followed by Cigna and Beccaria in the 1750s: the color change of the blood. Cigna's summary of this work, published in the first volume of the Miscellanea Taurinensis, was an attack on physicists who believed that the red color of the blood depended on the density of the red particles." Since Cigna found that any portion of a black clot of blood could be reddened by exposure to air or kept black by exclusion from air, he argued that redness must depend on the arrangement of blood and air corpuscles in arterial blood.10 The conclusion of Cigna's paper was addressed to physicians who faced examples of unnatural redness, blackness, foaming, or coagulation of the blood in vivo. The one connection between Cigna's study of the blood and Lagrange's theory of heat production was a belief that the air enters the blood and plays an active role within the animal." Cigna did not emphasize this point in his paper but his fellowstudent, G. A. F. Eandi, tells us that the issues under discussion in Beccaria's laboratory at this time were the entrance of the air into the blood, the state of the air in the blood, and the function served by the air in the animal.1'2 Beccaria, who was eager to convert the university from Cartesian to Newtonian physics,13 argued with a colleague over a dramatic vivisectional experiment:

14

He exposed the jugular vein of an almost senseless calf; this he ligated tightly in two places several finger breadths apart. He then removed the central portion in the presence of his colleague and several assistants. He placed it under the pneumatic pump and extracted the air. At each blow of the piston we saw bubbles and swellings emerge from this piece of the jugular. When the bubbles had subsided, I cut the jugular swollen with a very sharp lancet. The blood spurted out, foaming up like the Furies. tione," Misc. Taur., 5: 109-161; I will discuss these papers in detail elsewhere. 9. Cigna, "De colore sanguinis experimenta nonnula," Misc. Taur., 1 (1759), 68-75. 10. Ibid., 68, 71-72. 11. Ibid., 74-75. 12. G. A. F. Eandi, Memorie istoriche intorno gli studi del padre Beccaria (Turin, 1783), 70-72. 13. Antonio Pace, Franklin and Italy (Philadelphia, 1958), chap. 3. 14. Eandi, Memorie . . . Beccaria (n. 12 above), 70.

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DIANA LONG HALL

A memorable demonstration of the existence of the air in blood, and of the elastic state of the air discharged from the bloodl But what was the state of the air in the blood? Beccaria argued on Newtonian principles that the air in blood must be inelastic. Unlike many Newtonian physiologists he also argued that it was nevertheless active, the agent responsible for the proper fluidity of the blood and the ability of the body to adjust slowly to changes in external air pressure.'5 Lagrange also argued that the oxygen of the air is dissolved by the blood and plays an active role. The gas was not air, and the role was heat and not color or fluidity, but the physiological theory, the emergence of the process within the animal, was similar. I have attempted to show indirectly the connection between Lagrange's later theory of respiration and his experience as a young man at Turin. Lagrange's involvement with Cigna's iatromechanical and pneumatic experiments and the parallel between Lagrange's later theory and Beccaria's 1758 theory raise new questions. What did Lagrange think of Beccaria's 1758 theory? By what process did he graft on to the New Chemistry the old question of the entrance of the air into the blood? What did he think of Cigna's later studies of respiration? Lagrange's published correspondence is incomplete and marked by reticence. There does exist a manuscript letter from Cigna to Lagrange relative to Cigna's study of the electrophore which I have not yet seen.'6 Two missing letters from Lagrange would also enrich our understanding of his relationship to physiology: his reply to Laplace's request for criticism of his and Lavoisier's heat theory in September 178317 and his letter sent before January 1767 asking Euler to find a place for Cigna at the Berlin Academy.'8 Perhaps we cannot find a connected story of Lagrange's physiological thought, but we do know that it had a definite beginning in the collaborative work of the Turin group in the 1750s. We know that Lagrange applied his physical ingenuity to experimental problems, and we infer from his friendship with Cigna that he participated in the frustrating efforts of the iatromechanists to make physiological sense of the physical properties of the air and the blood. 15. Ibid., 71-72, with reference to E. Halley, "the Art of Living Underwater," Phil. Trans., 29 (1714-15), 492-499. 16. Vassalli-Eandi," Memorie . . . Cigna," (n. 5 above), xxxvi. 17. Oeuvres de Lagrange, ed. J. A. Serrat (Paris, 1892), XIV, 123-124; I am grateful to Henry Guerlac who pointed out this letter to me. 18. Ibid., 210; reply from Euler 9 January 1767.

248

MeasuringMan'sNeeds* JANE O'HARA-MAY Subdepartment of the History of Medicine, University College London, England

Man's most fundamental need is for food. The questions "What foods should be eaten?" and "How much of them are required?" have been asked since man recognized a relationship between his food and his health. Empirical ration scales have been in use from ancient times; our word salary is, of course, derived from the term for money allowed to Roman soldiers to buy their salt ration. Early records of monasteries, hospitals, institutions for the poor, houses of correction, and the army and navy provide a variety of examples of ration allowances. These kinds of scales were based, very generally, on such things as tradition, religious and practical factors, money available, and the apparent health of those taking the ration. They continued in use with some variations for centuries. It was not until the mid-nineteenth century that a workable quantitative basis for calculating the food requirements of man was established. The first generally accepted figures were those of the Dutch physician Jacob Moleschott (1822-1893) published originally in Wiener Medizinische Wochenschrifte, May 14, 1859.1 and then included in the second edition of his Physiologie der Nahrungsmittel: ein Handbuch der Didtetik.2 Moleschott's "numbers" or "figures," as they were called, referred to the amounts of chemical elements required from food in terms of alimentary principles.3 His calculations indicated the needs, per day, of an * Paper presented to the British Society for the History of Science, March 16, 1970. Research for this paper was done during the tenure of a Research Fellowship awarded by the Wellcome Trust. The support is gratefully acknowledged. 1. "Von der Menge, in welcher die einzelnen Nahrungsstoffe zu einer vollstandigen Erhahrung erfordert werden" was section VIII. 2. Published in Giessen by Ferber in 1859. The first edition was published in Darmstadt in 1850 and was based on the work of Moleschott's former teacher, F. Tiedmann (1787-1861). 3. Alimentary principles were understood to be "all those compounds which are either identical with the essential constituents of blood, or Journal of the History of Biology, vol. 4, no. 2 (Fall 1971), pp. 249-273.

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JANE O'HARA-MAY

active man of average body weight, and provided a standard still referred to by writers in the twentieth century.4 The object of this paper is to consider some of the developments in thought that enabled Moleschott to formulate his quantified dietary standard. The delay in providing such a standard was certainly not due to lack of interest. This is clearly shown by the emphatic way in which writers, through the centuries, have explained that a standard diet was impossible to formulate. Thomas Newton translating Gratarolus in 1574 said: "Even as a shoomaker cannot make one shooe to serve every mannes foote, so neither can a Phisicion describe and appoint any one generall order and dietarie for all manner of persons." 5 Under the humoral doctrine, accepted in the sixteenth century, it was particularly difficult to make any standard for food intake because the predominant qualities in foods (i.e., hot or cold, dry or moist) acted upon the dominant qualities of the body, and their effect therefore depended upon the complexion of the eater.6 Besides this, food and drink were only one of six non-naturals (air; meat and drink; sleep and watch; movement and rest; emptiness and repletion; and affections of the mind),7 all of which had to be considered when formulating the whole diet or regimen. At that time and in subsequent centuries the appetite was relied upon as a proper guide to the quantity of food required. In the nineteenth century, with the recognition that the body and foodstuffs were composed of the same basic chemical elements and the rejection of the traditional idea of "one aliment," 8 it was possible to be more specific about the human body's needs for various foods. However, J. A. Paris, himself an advocate of the application of chemical ideas to medicine, says in his Treatise sufficiently similar to be transformed into them by digestion." This definition is given on p. 331 of "The Chemistry of Food" (i.e., E. Bronner's translation of Moleschott's Lehre der Nahrungsmittel de Volk) in Onr's Circle of the Sciences: Practical Chemistry, G. Gore, M. Sparling, and J. Scoffern eds. (London: Houlston & Stoneman, 1856). 4. R. Hutchison and V. H. Mottram, Food and the Principles of Dietetics, 7th ed. (London: Arnold, 1933), p. 42. (1st ed., 1900) Here, only the figure for protein (albuminous material) agrees exactly with Moleschott's original. 5. Gulielmus Gratarolus, A Direction for the Health of Magistrates and Students, trans. T. Newton (London: William How, 1547), Sig. B3r. 6. Individuals could be grouped under four types of complexions or temperaments; Sanguine (hot: moist); Choleric (hot: dry); Phlegmatic (cold: moist) and Melancholy (cold: dry). 7. This list of six non-naturals is taken from T. Elyot, The Castel of Helth (London: T. Berthele, 1541), Sig. B1'. 8. The tradition of "one aliment" is said to be derived from Hippocrates. de It was questioned by F. Magendie (1783-1855) in Pr&cis el6mentaire physiologie (Paris: Mequignon-Marvis, 1816), II, 3, n. 1, and rejected by

250

Measuring Man's Needs on Diet (1837) that it is absurd to try to establish a rule of weight and measure for the quantity of food which ought to be taken, as the capacities of individuals vary so greatly.9 Despite the attitude of physicians, from the sixteenth century onward a kind of standard had been chosen. This was the strict regimen of a Venetian gentleman named Luigi Cornaro, who stated that he had lived to a vigorous old age by taking only 12 ounces of food and 14 ounces of wine each day. His story is particularly dramatic because at about forty years of age he was near to death due to an excessive way of life, but he was reprieved by turning to his strict diet and lived to be more than one hundred years old.'0 Since his death in 1566 Cornaro's diet has been referred to constantly by such diverse authors as Mr. Addison in The Spectator of 1711 and Miller and Payne in the 1969 Proceedings of the Nutrition Society." The references through the centuries are so numerous that one feels inclined to reiterate with Father Feyjoo of Montenegro (in his Treatro Critico of 1733) that surely "God did not create Lewis Cornaro to be a rule for all mankind in what they eat or drink." 12 In the 1855 edition of Principles of Human Physiology, W. B. Carpenter refers to Cornaro's diet but in terms of a subsistence level. He repeats that appetite is the only guide and that no universal law can be laid down regarding the quantities of food to be taken. He adds that it is important, from the practical point of view, to form a correct average estimate of what is needed.13 Today we all agree, with Gratarolus, that it is impossible to make a shoe to fit every foot. The modern approach is to try to make what might be called an overshoe intended to be suitable for the feet of all the people within a particular group. This is the approach used in the recent Recommended Intakes of Nutrients for the United Kingdom (1969), which provides figures for ten nutrients with additional advice on more than William Prout (1785-1850) in "On the ultimate composition of simple alimentary substances," Phil. Trans. Roy. Soc., London (1827), pt. 2, 355-388. 9. J. A. Paris, A Treatise on Diet, 5th ed. (London: Sherwood, Gilbert & Piper, 1837), p. 148. (lst ed., 1826). Paris also wrote The Elements of Medical Chemistry (London: Phillips, 1825). 10. See Lewis Cornaro (trans. from the Italian), Sure Methods of attaining a Long and Healthful Life: with the means of correcting a bad constitution, 34th ed. (London: J. Anderson, 1822). 11. Joseph Addison, The Spectator, no. 195, Oct. 13, 1711; D. S. Miller and P. R. Payne, "Assessment of protein Requirements," proc. Nutr. Soc., 28 (1969), 226. 12. B. G. Feyjoo y Montenegro (trans. from the Spanish), Rules for Preserving Health (London: R. Fauldner, 1800), p. 82. 13. W. B. Carpenter (1813-1885), Principles of Human Physiology, 5th ed. (London: J. Churchill, 1855), pp. 45 and 47. (1st ed., 1843).

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JANE O'HARA-MAY

fourteen others not tabulated. The information given is applicable to people in twenty-one different groups of the population.14 The tables are based on accepted chemical and physical laws which are quantifiable and general in their application, and derived, on the whole, from the early nineteenth century. Nutrients, used as units, are identifiable by their chemical composition; this can be equally well applied to the needs of the human body or, with the help of food composition tables, to the contents of foodstuffs. A study of modern tables and Moleschott's comparatively rudimentary recommendations shows that his work is clearly a forerunner of today's methods. At the beginning of his chapter entitled "On the Quantity of Different Individual Foods Required for Complete Nourishment" Moleschott said: The statement that one cannot determine the quantity, by weight, of foods needed by man is based on the fact that people have continuously forgotten to ask themselves for what unit of body weight and time the weight [of the food] ratios should be given."'5 Moleschott then explained that by using precisely defined units and by considering the various demands made upon man, a carefully calculated minimum requirement of food can be established.16 The figures he gave are shown in Table 1. Table I For a Working Man Weighing 63.65 kg'7 Per day Active Nitrogenous Nitrogen-free

Resting

Albuminous material

130g.

fat fat-former

84g. 488g. 404g.

Salt

60g.

5

430g.

30g.

Water TOTAL

2,800g. 3,448g.

14. Great Britain, Department of Health and Social Security, Recommended Intakes of Nutrients for the United Kingdom, Reports on Public Health and Medical Subjects no. 120 (London: H.M.S.O., 1969). The latest U.S. National Research Council figures for Recommended Dietary Allowances tabulate seventeen nutrients and refer to twenty-six groups. 15. Moleschott, Physiologie (1859), pp. 216-217. 16. Ibid., p. 217. 17. Ibid., pp. 223, 225.

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Measuring Man's Needs Comments on Table 1 Moleschott followed Liebig's theories, first put forward in Animal Chemistry (1842),18 and gave his quantities in terms of nitrogenous (plastic) materials capable of supporting growth and movement and nitrogen-free (respiratory) materials which provided heat for the body. Because movement was considered to result from the breakdovvn of nitrogenous tissues a resting man required fewer albuminous foods. The quantity of heatgiving foods remained approximately the same. Moleschott used the term Fettbildner for carbohydrates, although Carl Schmidt had introduced the word carbohydrate in 1844.19 In the controversy over the formation of body fat from amylaceous materials, Moleschott believed that fat could be formed in the body from carbohydrates.20 The following ratios were given, N:N-free 1:3.7; fat to f atformers 1:4.84. The standard provided Nitrogen 308.6 grains or 20g. Carbon 4,629 grains or 300g. The weights of alimentary principles were given as "waterfree," their water content being included in the total water. Earlier in the century Berzelius had improved his analytical techniques by drying his material, and later William Prout had stressed the necessity of drying foods to be analyzed.21 Tables of food analysis show that some foods were dried to 212?F or in vacuo 230'F.22 For some years after the publication of Moleschott's figures standards were sometimes given in terms of 'water-free' foods. Care has to be taken not to confuse this meaning of 'dry' with the term 'dry foods' which was used to differentiate between dry foods and drinks. 18. J. Liebig, Animal Chemistry, or Organic Chemistry in its applications to Physiology and Pathology . . . Edited from the author's manuscript by W. Gregory (London: Taylor & Walton, 1842). 19. C. Schmidt (1822-1894) [Liebig's] Annalen der Chemie, 51 (1844), 30. In "The Chemistry of Food" (see n. 3 above) p. 308, Moleschott described starch, gum, and sugar as important constituents of fat. 20. In this he followed the German school of thought under Liebig. During the controversy many French workers (e.g., J. B. A. Dumas and J. B. Boussingault) held the view that all fat in the body was derived from the fat in foods. 21. W. H. Brock, "The Life and Work of William Prout," Medical History, 9 (1965), 101-126. 22. See J. Pereira, A Treatise on Food and Diet (London: Longman, Brown, Green & Longmans, 1843), p. 80.

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The energy value of Moleschott's standard was estimated by later workers as 3,160 kcal,23 although this figure can vary according to the method of calculation used. Moleschott obtained his results by using two methods checked against each other. 1) By studying the food intakes of healthy active men. He used twenty-one reported dietaries, collected by seven workers from various countries. 2) By observation and by calculation, he related the amount of nitrogen, carbon, hydrogen, and oxygen excreted, in twenty-four hours, by his "reference man," back to food intake. He recognized that this method could give only a rough representation of the food eaten, but he believed it to be a useful check. Basically, this is a similar method to that used today, which still fundamentally depends on the results of dietary surveys and metabolic balance studies. However, Moleschott in his detailed calculations used too many related assumptions for his calculations to be compared directly with modern methods.24 It is on the background to the following three points, raised by Moleschott's work, that comment is given in this paper: A) The use of the unit of body weight; B) The studies of food intakes available to him; C) The attempts to balance food intakes and excretions. A) THE UNIT OF BODY WEIGHT The figure 63.65 kg used by Moleschott as his reference unit of body weight comes from the works of Adolphe Quetelet ( 17961874), the Belgian astronomer, mathematician, and statistician. The use of this figure is of interest both from the point of view of body-weight records and from the whole concept of the average man. Today most of us are likely to have been weighed and measured at some time in adult life, but the taking of this type of record is of recent origin. In the past, the comparative weight of healthy adults was not thought to have any particular significance, though sick persons, cared for in monasteries, had 23. Hutchison and Mottram, Food and Dietetics, p. 42. 24. Moleschott used ratios (e.g., N:N-free) from his dietary intake figures in his calculation of food intake from excretions. The results of this calculation were then used as a check against the suitability of the dietary records he had used.

254

Measuring Man's Needs been weighed as part of their treatment in some cases. Abbe Jaubert, writing in 1764, said that the chapel of La Balance derived its name from this custom.25 The use of measurement to determine the rates of human growth is said to have originated with Buffon,26 and workers in the next century developed this method. In France, F. Chaussier measured the growth of infants and in England W. R. Cowell reported to the Factory Commission of 1833 on the comparative heights and weights of children working in factories and of those outside.27 Before the nineteenth century, apart from individual cases, few records are available of the heights and weights of healthy adults. In 1793 the famous French physician J.-R. Tenon weighed and measured sixty men in a village outside Paris, while concern about the poor physique of army recruits led first to the work of A. A. Hargenvilliers28 and later to the surveys of L.-R. ViIlerme in 1829.29 About this time a number of students were weighed and measured at Cambridge University, for Quetelet reports that William Whewell sent him some eighty records.30 The first comprehensive records of adult body-weight can be found in "Recherches sur le poids de l'homme aux differens ages," published by Quetelet in Nouveaux memoires de l'Academie Royale des Science et Belle lettres de Bruxelles (1833).31 This material was repeated in subsequent publications, including Quetelet's important work Sur l'homme et le developpement de ses facultes of 1855.32 25. P. Jaubert, Dictionnaire Taisonne universel des arts et mgtiers (Paris: Didot jeune, 1773), III, 445. (lst ed., 1764). 26. Le Comte de Buffon (1707-1788), L'Histoire naturelle (Paris: Imprimerie Royale, 1749), L'Histoire naturelle de l'homme, p. 472. 27. F. Chaussier (1746-1828), M6moire medico-legal sur la viabilit6 de l'enfant naissant (Paris: Comp&re jeune, 1826). W. R. Cowell, Great Britain: Accounts and Papers (1833) (450) xx-xxi, First Report of Commissioners in Manufacturing Districts Relative to the Employment of Children in Factories, sect. D.I. 28. A. A. Hargenvilliers (1768-1835), Recherches et conside6rations sur la formation et le recrutement de l'armee frangaise (Paris; Firmin-Didot & Maginel, 1817). 29. L. R. Villerm6 (1782-1863), "La taille de l'homme en France," Annales d'hygiene publique et m6dicine lgale, 1 (1829), 351-400. 30. Despite kind advice from the keeper of the Archives of Cambridge University (Miss H. E. Peek) these records have not been traced. 31. A. Quetelet, Nouveaux M6moires. . . . [The title of this journal is now changed to] Academie Royale des Science des Lettres et des Beaux Arts de Belgique, 7 (1831-32), 38 pp. Work presented in 1832 published in 1833. Quetelet is sometimes referred to by his full name, Lambert Adolphe Jacques. 32. A. Quetelet, Sur l'homme, et le d6veloppement de ses facult6s (Paris: Bachelier, 1835).

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JANE

O'HARA-MAY

To understand the importance of the Treatise on Man (the English translation appeared in 1842)33 it is necessary to look at Quetelet's place in the history of statistics. Adolphe Quetelet drew together the three main statistical developments and tendencies of his time: 1) The method in which verbal analysis and description were used to cover the life and organization of the state. This method originated with the work of Hermann Conring (1606-1681) in the seventeenth century and was continued in the next century by Gottfried Achenwall (1719-1772). 2) The school of "Political Arithmetic" begun by John Graunt (1620-1674) and followed by William Petty (1623-1687). 3) The development of the mathematical theory of probability.34 By combining and developing these approaches, Quetelet sought to understand man's situation in his society through the study of the development and general faculties of man himself. In his Treatise on Man Quetelet divided his subject into four sections, with these titles.35 BOOK

i

Development of the physical qualities of man. The material is concerned with the levels and causes of birth and mortality rates.

BOOK ii

Development of stature, weight and strength, etc.

BOOK III

Development of the moral and intelectual qualities of man. Moral qualities were judged to be "Foresight, Temperance, Activity, etc." Intellectual qualities of different populations were compared by such criteria as the age of successful dramatists and the incidence of insanity.

BOOK

IV Of the properties of the average man; of the social system, and of the final advancement of this study.

Previous memoirs are included and developed in this work, and the concept of the average man (homme moyen) is clearly put 33. Treatise on Man, trans. "under the superintendence of Dr. R. Knox" (Edinburgh: W. and R. Chambers, 1842). 34. Malthus, La Place, and Fourier were all known personally to Quetelet. For Quetelet's contribution to the theory of probability see Helen M. Walker, Studies in the History of Statistical Method (Baltimore: Williams and Wilkins, 1929). 35. Quetelet, Treatise on Man, bk. I, p. 9; bk. II, p. 57; bk. III, p. 72; bk. IV, p. 96.

256

Measuring Man's Needs forward. F. F. Hankins, in his "Adolphe Quetelet as Statistitian," 36 suggests that this concept is the unifying principle found throughout the wide range of Quetelet's works on population, moral statistics, physical anthropology, and the social system in general. Through this reiteration, the idea came to be widely disseminated. Quetelet's concept of the average man changed from that of the early memoirs, which had depended upon direct measurements. Originally he had said: The man that I consider here is analogous to the centre of gravity in bodies; he is the mean about which oscillate the social elements; he is, so to speak, a fictitious being for whom all things proceed conformly to the average results obtained for society. If we wish to establish the basis of a social mechanics (mecanique sociale), it is he whom we should consider, without stopping to examine particular or anomalous cases.37 Later, Quetelet developed the view of the average man as a biological type about which the actual men of a given group were distributed according to the normal law of error, or the "law of accidental causes," as Quetelet called it.38 Moleschott, like Quetelet, recognized that the average man could not be constructed as a composite being, and he stressed that his calculations should be applied to the majority, for, as he said, we should always remember that "an individual is indeed to some measure an individual just because he does not fit into a line of arithmetical means." '9 Nevertheless, as Moleschott himself had pointed out, it was on the basis of unit of body weight and unit of time that a quantifiable standard of food requirement could be constructed. B) DIETARIES Reference has already been made to ration scales. The example shown in Table 2 is from a sixteenth-century "House of Correction." 36. F. F. Hankins, "Adolphe Quetelet as Statistitian," Studies in History, Economics, and Public Law (New York: Columbia University) 31 (1908), no. 4. 37. Ibid., p. 63. The translation is by Hankins. 38. Ibid., p. 67. 39. Moleschott, Physiologie, p. 226.

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JANE O'HARA-MAY

Table 2 Maximum Daily Allowance per Person40 Flesh days Rye bread

8 oz (troy weight)

Porridge

1 pint

Flesh (unspecified)

1/4lb

Beer

1 pint (quality varied with cost)

Those who worked hard had "a little more" beer and bread between meals. Those who would not work received only beer and bread. From a scale of this type is was impossible to estimate the intake of individuals or groups from over-all figures. The twenty-one dietaries used by Moleschott for his calculations were assumed to be the actual intake of the people involved. Some, such as those of sailors and soldiers, were naturally related to their ration scales. Moleschott's stated object in using figures from a variety or diets was to determine empirically and directly how much albuminous matter, fat and fat-formers, salt and water a hard-working man takes in 24 hours if he is not prevented by either need or prejudice from completely satisfying the need for nourishment he feels to be necessary.41 It was assumed that the soldiers, sailors, farm workers, peasants, and railway workers taking the foods listed were in the happy position of being able to satisfy their needs. The figures Moleschott used came from the period 1842-1856, and the wide selection of recorded dietaries then available indicates a marked increase in the study of diets in various countries during that period. It is, of course, impossible to pinpoint the reason for this interest, but some of the contributing factors may be indicated under the following headings: (i) Humanitarian; (ii) Practical; and (iii) Scientific, i.e., the effect of the developments in scientific thought and techniques. These headings also cover three factors essential to the general implementation of any new ideas-a suitable climate of opinion, an expediential need, and the availability of proper techniques to do the task. 40. From "Orders . . . for the House of Correction at Bury, Suffolk" (1588); see F. E. Eden, The State of the Poor (London: J. Davis for B. & J. VVhite, 1797), vol. III, App. cxliii. 41. Moleschott, Physiologie, p. 217.

258

Measuring Man's Needs It will be seen from the examples used by Moleschott that the investigation of diets was taking place in various countries at this time. Here, the illustrative references given have been chosen from a British context. (i) Humanitarian factors The French Revolution and the impact of such writings as Tom Paine's The Rights of Man provided a climate of awareness about the ordinary man and his problems. An indication of the confusion of contemporary thought in the early nineteenth century about the proper action to be taken to help the laboring classes is found in the studies of Sydney and Beatrice Webb and J. R. Poynter.42 All approaches to the problem necessitated investigation into the conditions of life of the working man. (ii) Practical factors Consideration of the diets of various groups of the population was forced on the authorities for practical reasons. The Naval mutiny of 1797 caused far-reaching reforms, among which were changes in naval ration scales. These were altered in 1825 and again in 1844. It was said of the 1844 scale that there could be no "complaint of an insufficiency of food, although the allowance [31-35 oz nutritious matter daily] cannot be regarded as superfluous."43 Dietary conditions in the Army were brought to the notice of the public through the Crimean War (1854-1856), but earlier the high mortality rate of troops at overseas stations had resulted in a series of reports, such as Marshall and Tulloch's Statistical report on the Sickness, Mortality and Invaliding among troops in the West Indies (1838).44 This was one of many such reports advocating an improvement in Army diet. At home the high prices of food in 1795 led to the introduction of the Speenhamland System which provided a scale of outdoor relief. This scale was based on the price of bread and the size of the family.45 Continuing destitution and the rapid rise of the Poor Rate led to the Poor Law Amendment Act of 1834, the basis of which was the abolition of outdoor relief for the ablebodied poor and the concentration of the care of the needy in 42. S. and B. Webb, English Poor Law History (London: F. Cass, 1963), pt. II, vol. I. First edition 1929: J. Poynter, Society and Pauperism (London: Routledge & Kegan Paul, 1969). 43. Carpenter, Human Physiology, p. 45. 44. Great Britain, Army Medical Services: H. Marshall and A. M. Tulloch, Statistical Report on the Sickness, Mortality and Invaliding among Troops in the West Indies (London: W. Clowes, 1838). 45. Webb, Poor Law History, pp. 177-178.

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Union Workhouses. In 1836 the Poor Law Commissioners suggested six general dietaries (based on past usage) to be used by the guardians for able-bodied men and women in workhouses. The important point underlying the use of these diets was that they must not be better than "the ordinary levels of subsistence of the labouring classes of the district."46 The need to determine this level of subsistence led to further investigations into the standard of living of laborers and agricultural workers in various parts of the country. (iii) Scientific factors The important relationship between the development of elementary analysis and the origins of physiological chemistry has been well described by F. L. Holmes.47 The new techniques of analysis were quickly applied to a wide variety of foodstuffs. In 1816 Francois Magendie had shown that animals could not live on one type of food alone,48 and a number of other workers in aniimal nutrition had investigated the nutritive value of different foods. Following Thaer's table of hay-equivalents of 1812, Boussingault produced his Table of Equivalents, based on nitrogen content, in 1844.49 This table gave quantities of different kinds of vegetable foods which, theoretically, would produce the same effects on the growth of muscle in animals. From his work on calculating proper rations for animals, R. D. Thomson, in 1846, emphasized the great importance of the ratio of nitrogenous to nitrogen-free foods in the diet.50 This ratio, given in terms of the nitrogen and carbon contents of a diet, came to be used for the comparison of the value of different food intakes. By Moleschott's time the techniques available for estimating and comparing the value of different foods had given a new sigficance to the study of dietary intakes. The dietaries used by Moleschott came from the following authors

51

MULDER

two examples of soldiers

46. Great Britain, Poor Law Commissioners, Edwin Chadwick, Second Annual Report of the Poor Law Commissioners for England and Wales (London: W. Clowes, 1836), p. 63. 47. F. L. Holmes, "Elementary Analysis and the Origins of Physiological Chemistry," Isis, 54 (1963), 51-81. 48. F. Magendie, "Memoire sur les proprietes nutritives des substances qui ne contiennent pas azote," Ann. Chim. Phys., 3 (1816), 66-77. 49. J. Boussingault (1802-1887), Economie rurale (Paris: Bechet jeune, 1844), p. 483. 50. R. D. Thomson (1811-1864), Experimental Researches on the Food of Animals (London: Longman, 1846), p. 165. 51. Moleschott, Physiologie, p. 218.

260

Measuring Man's Needs PLAYFAIR

eight examples of soldiers, sailors, and agricultural laborers

LIEBIG

one example of soldiers

GASPARIN one example PAYEN WUNDT GENTH)

of a "French worker"

seven examples of a sailor, workers, peasants, handworkers and English railway workers self-observations

Comments on Authors and Diets The dietaries selected by Moleschott came from the works of authors with widely differing backgrounds. Details were rarely given of how the dietary records were collected. MULDER, G. J. (1802-1880) Dutch physiologist, famous for his theory that there was one radical in albuminous-type materials which he called proteine. One-time teacher of Moleschott (who translated some of his works into German), Mulder's reference to the diet of Dutch soldiers was incidental to his discussion of the value of foods.52 PLAYFAIR, LYON (1819-1898), one-time pupil of Liebig; Secretary to the Department of Science and Arts in Britain; later Professor of Chemistry in Edinburgh and Member of Parliament. The figures used were taken from his paper entitled "The Food of Man under Different Conditions of Age and Employment," given at the Royal Institution in 1853.53 From this article Moleschott used records of English, French, and Bavarian soldiers, and English sailors under various conditions. LIEBIG, JUSTUS VON (1803-1873). Details of the diet of Hessian soldiers were given in his Animal Chemistry. Accurate observations were made, for a month, on the food intake of 27-30 soldiers in barracks. The quantity of food taken outside was given in "an approximate" report by the sergeant-major. The total intake of food was added up, and this quantity was taken as the daily intake for 855 men. Moleschott's figures were taken from this total as the average per man per day.54 GASPARIN, A. E. P. DE (1783-1862), French authority on 52. G. J. Mulder, Die Ernnahrung in ihrem Zusammenhange mit dem Volksgeist (Utrecht, Dusseldorf: Bottischer, 1847), p. 59. 53. Lyon Playfair, "The Food of Man under Different Conditions of Age and Employment," Proc. Roy. Inst. of G. Brit., 1 (1853), 313-317. 54. Liebig, Animal Chemistry, pp. 285-289.

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agriculture, author of the famous Cours d'agriculture, 1843186055 Gasparin wished to relate food intake to work done and used figures from Quetelet and Villerme to do this. Details of the diets of agricultural workers were placed under the section on Farm Management in the part dealing with Capital Investment. Under this heading Gasparin included items related to the health and working ability of men and beasts. PAYEN, ANSELM (1795-1871) French industrial chemist of high repute. The diets were taken from Des substances alimentaires.56 Here Payen records and comments on diets taken from a number of sources including Gasparin's Cours d'agriculture. One of particular interest is that of the English railway workers who were working on the Rouen railway.57 Their larger daily ration of meat was thought to account for the fact that they did so much more work than their French counterparts. This comparison was frequently quoted by later writers to illustrate the importance of meat in the diet when doing hard work. GENTH, A. E., was a physician at the Spa at Wiesbaden. The information about his diet came from his study of the effects of drinking water.58 WUNDT. This individual has not yet been definitely identified, but he may have been a student at Heidelberg in Moleschott's time.

Moleschott did not, himself, record any diets for the purpose of his calculations, and obviously the dietaries he used had not been designed for that purpose. The records he chose contained the information he needed for his calculations, though no single diet provided information on all the points that interested him. These points were: The total weight of nitrogenous material eaten:

figures available from all diets

The total nitrogen-free material from 13 diets (fat and carbohydrate): 55. A. E P. de Gasparin, Cours d'Agriculture (Paris: Maison Rustique, 1843-1860), V, 387-398; and see also III, 51. 56. A. Payen, Des substances alimentaires (Paris: Hachette, 1853), pp. 339-386. 57. Ibid., p. 376. 58. E. A. Genth, Untersuchungen euber den Einfluss des Wassertrinkens auf den Stoffwechsel, nebst einigen Bemerkungen, betreffend die in der Wasserheilanstalt Nerothal iubliche Verbindung der Bewegungs-Heilmethode mit Wassercur (Wiesbaden: Kreidel & Niedner, 1856).

262

Measuring Man's Needs The ratio of nitrogenous to nitrogen-free foods:

from 13 diets

The ratio of fat to f atformers:

from Wundt and Genth

Salt intake:

from 13 diets

The total water was calculated from excretion figures. Moleschott wished to relate his findings back to his "reference man" of 63.65 kg, but of all the diets he used, only those from Gasparin and Genth were given in relation to body weight. The diets of Moleschott used were for the most part chosen from the publications of well-known men. These were, in fact, only a small part of those records available in the 1850s. Moleschott does not, for example, refer to Die Normal-Diat by W. Hildesheim, published in Berlin in 1856,59 in which the author attempts to determine a normal diet through an examination of metabolic studies and dietary intakes. C) BALANCE STUDIES Moleschott checked the suitability of these dietary intakes against the matter excreted by his "reference man" in 24 hours. He recognized that this method would give a low figure for food intake because it was not possible to measure accurately all body losses. His method was based on the belief that for a normal, healthy adult output is equivalent to intake. A proper balance between the intake and excretions of the body was a fundamental part of many theories of health, and a study of this balance has long been used to investigate metabolic processes. The first precise measurement we have of intake related to output is that of Sanctorius (1561-1636). Sanctorius worked in Padua and for more than thirty years studied the weight of insensible perspiration (including vapor lost from the lungs) in relation to the six non-naturals. His findings are found in "Aphorisms" in the Medicina Statica.60 Dr. James Keill (1673-1719) of Northampton did a similar study in the English climate. His results are published, together with John Quincy's translation of 59. W. Hildesheim, Die Normal-Diat; Physiologisch-chemischer versuch zur Ermittelung des Normalen Nahrungsbedrifnisses der Menschen, behufs Aufstellung einer Normal-Diat (Berlin: Hirschwald, 1856). 60. Sanctorius' Medicina Statica was a familiar work. It had been 'Englished' by J(ohn) D(avis) in 1676 (London: J. Starkey )and was commented on by Martin Lister: S. Sanctorii de Statica Medicina . . . cum Commentario (London: Smith & Walford, 1701).

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Sanctorius' Aphorisms, in Medicina Statica Britannica of 1728.01 Among Keill's sixty-six aphorisms are these: APH. 8 "In a most healthful state the Quantity ejected is equal to the Quantity taken in." APH. 40 "The natural Discharges are not in proportion to the weight of the Body, but the Quantity of Diet taken in." APH. 43 "If the Quantity of food be greater or lesser than needful, then it will not answer to the Quantities evacuated: for whether we eat more or less, Nature always keeps a certain Rule in Evacuation.",62 Despite the recognition of this last rule, excretions were still considered to be in proportion to intake because, it was said, "the rule admits wide latitude" and, in any case, depended on the powers of digestion.63 The relationship between the weights of food intake and excretions was confirmed some ten years later in Bryan Robinson's Dissertation on the Food and Discharges of the Human Body,64in which the author combined his own results with Keill's and with material from George Rye's Medicina Statica Hibernica (1734)6f5 and the reports of John Lining of South Carolina (1708-1760) .66 All their figures show that the weight of food taken about equals the weight of excretions. Robinson believed that the quantity of material discharged was governed by the motion of the blood. In Proposition II he writes: The sum of the Discharges by Perspiration (p), Urine (u), and stool(s), in a Natural day or any other Time, is nearly proportional to the mean Quantity of Blood, which in that Time flows out of the Heart into the Aorta in one Systole (q), and the Number of Systoles or Pukes in the same Time taken together (N). 61. John Quincy (d. 1722), Medicina Statica Britannica, 4th ed. (London: Osborne & Longman, 1728). 62. Ibid., p. 323, 335, 336. 63. Ibid., p. 337. The concept of homeostasis was developed from the work of Claude Bernard and introduced in the twentieth century by Walter B. Cannon in The Wisdom of the Human Body (New York: W. W. Norton, 1932), p. 24. 64. Bryan Robinson (born 1679) A Dissertation on the Food and Discharges of Human Bodies (London: J. Nourse, 1748). 65. George Rye, "Medica Statica Hibernica" can be found as the second part (p. 189 et seq.) of Joseph Rogers' An Essay on Epidemic Diseases . . . (Dublin: printed by S. Powell for W. Smith, 1734). 66. Lining's results were published in Phil. Trans. Roy. Soc. 42 (1743), 491-509; 43 (1745), 318-330.

264

Measuring Man's Needs And he gives the formula, p + u + s is nearly proportional to qN67 Robinson's primary concern was with the quantity of material taken in and excreted. Later workers took somewhat different approaches. William Cruickshank, for example, was concerned with the composition as well as with the quantity of insensible perspiration. He first published his Experiments on the Insensible Perspiration of the Human Body showing its Affinity to Respiration in 1779 and republished it in 1795.68 He believed that the skin could absorb and excrete "air,"and he thought that the composition of insensible perspiration was similar in effect to expired air-a point over which he came into collision with Priestley. In the early nineteenth century it was known that if excreted matter was to be related to intake in terms of quality as well as quantity the connection should be through the chemical elements of nitrogen, carbon, hydrogen, and oxygen, and at that time much experimental research was done along these lines. The analysis of urine, sweat, and feces done by Berzelius in 1806 remained a standard for many years, being commended in 1820 by Thomas Thomson (1773-1859)69 and by later writers such as C. G. Lehmann in his Physiological Chemistry.70 Regarding excretion through the lungs, the work of Allen and Pepys on human respiration, published in 1809, is particularly notable.7' But before elemental intake could be equated with output, the idea that elements could be produced during metabolism had to be discarded. In 1799 L. N. Vauquelin had demonstrated by experiment that the hen could generate calcium.72 In 1838 Thomas Thomson had been uncertain that fixed principles were produced by growing plants,73 and by 1843 Pereira still felt it was necessary to make the point, more than once, that "a living body has no power of forming elements, or of converting one 67. Robinson, Food and Discharges, p. 28. 68. William Cruikshank (1745-1800), Experiments on the Insensible Perspiration of the Human Body showing its Affinity to Respiration, first published with other material in 1779, "republished with additions and corrections," 1795, (London: printed for G. Nicol). 69. Thomas Thomson, A System of Chemistry, 6th ed. (London: Baldwin, Craddock & Joy, 1820), IV, 536, 539, 553. 70. Translated by G. E. Day from the German edition of 1850 (London: Cavendish Society, 1851-1854), II, 384. 71. W. Allen and W. H. Pepys, Phil. Trans. Roy. Soc., 2 (1809), 404-429. 72. L. N. Vauquelin (1763-1829), Ann. Chim. 29 (1799 or An. VII), 3-26. 73. T. Thomson, Chemistry of Organic Vegetables (London: Bailli6re, 1838), p. 972.

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O'HARA-MAY

elementary substance into another." 74 For some time thereafter the definition and theory of chemical elements and the question of their immutability remained subjects for controversy.75 As far as human metabolic balance studies were concerned, by Moleschott's time is was generally accepted that the elements in the body must have been obtained from outside the body, the obvious source being food. This still left the question of whether atmospheric nitrogen could be used by the body and would appear in nitrogen balance results. Though Boussingault's work on "metamorphosis" in 1844 had shown that atmospheric nitrogen was not used by animals as a food,76 the subject continued to be controversial. It might have been hoped that the use of more precise techniques at this time would have lessened the likelihood of controversy. Far from it. One gains the impression that there can hardly have been a chemist of note who did not study some aspect of bodily excretion, nor a substance discovered which did not cause a verbal as well as a chemical reaction. During the 1850s research into metabolism included a large number of investigations of the volume and quality of body losses under normal and abnormal conditions. E. A. Parkes collected many of these results in his book on The Urine (1860).77 From a comparison of reports it was clear that even under normal conditions wide variations in results were possible. Nevertheless Moleschott used results of urine analysis as the base of his calculation of food intake from excretions. He took his figures from the results of ten researchers, including such well-known workers as Scharling, Barral, and Bischoff,78 adjusting their figures for his "reference man" as shown in the accompanying Table 3.79 He derived his calculations of food intake from the quantity of nitrogen excreted. Most of this nitrogen was in the urea, and the basis of his calculation was the relationship of urea to nitrogen intake. Some research workers believed that urea came in part from the breakdown of tissues and that part could also be formed from nitrogen in the food. Moleschott, like Liebig and Bischoff, belonged to the school of thought that believed urea to 74. Food and Diet, pp. 4, 468. 75. See David M. Knight, Atoms and Elements, a Study of Theories of Matter in England in the Nineteenth Century (London: Hutchison, 1967). 76. J. B. Boussingault, Ann. Chim. Phys., 12 (1844), 153-167. 77. E. A. Parkes (1819-1876), The Composition of the Urine in Health and Disease under the Action of Remedies (London: Churchill, 1860). 78. Moleschott, Physiologie, p. 58, Table LXX. References are to Scharling, Barral, Bischoff, Sherer, Rummel, Mosler, Hammond, von Franque, Kaup, and Schneller. Here the figure for uric acid is given as 0.61. 79. Ibid., p. 221.

266

Measuring Man's Needs Table 3 The Amount of Nitrogen, Carbon and Hydrogen in the Most Important Elements of Excretion Amount of matter in question for a bodyweight of 63.65 kg Grams in 24 hours Urea 31.3 Uric acid 0.31 Urinary pigment 7.79 Carbonic acid 963.29 Water 3119.78

N 14.60 0.20 0.69

15.49

Contained therein C H 6.26 2.08 0.21 0.01 4.55 0.40a 263.56 346.64 274.58 349.13

"Calculated according to Scherer's analysis.

be solely a product of the metamorphosis of nitrogenous tissues.80 From this point of view the nitrogen excreted in the urine could be taken to represent the nitrogen required by the body for the replacement of tissues, and therefore could also represent the required nitrogen intake from food in twenty-four hours. In the middle of the nineteenth century workers accepted the fact that the nitrogen balance of the body was not understood. The muchquoted work of C. Chossat8" on metabolism during inanition (1842) and the massive researches reported by Bidder and Schmidt in their Die Verdauungssaefte und der Stoffwechsel (1852)82 had given clues to the true situation regarding nitrogen balance: that is, that within limits the normal adult body adjusts its nitrogen output to intake, but equilibrium is not reached immediately when a change of intake occurs. Nitrogen balance figures continued in use for estimating protein needs until very recently.83 Moleschott's calculations assumed equilibrium. Using figures shown in Table 3 and Mulder's estimate that there was 15.5 percent nitrogen in albumin, Moleschott said that the nitrogen excreted (15.49 g), was equivalent to 100 g albumin. By subtracting the carbon present in this quantity 80. See G. E. Day (1815-1872), Chemistry in Relation to Physiology and Medicine (London. Bailli6re, 1860), pp. 37-49. 81. C. Chossat (1796-1875), "Recherches exp6rimentales sur l'inanition," Annales des Sciences naturelles (Zoologie), 20, (1843), 55-81, 182-214, 293-326. 82. F. Bidder (1810-1894) and C. Schmidt, Die Verdauungssaefte und der Stoffwechsel (Mitau, Leipzig: G. A. Reyher, 1852). 83. The latest (7th) revision (1968) of the U.S.A. N.R.C. Recommended Dietary Allowances is the first to discard the nitrogen equilibrium method for estimating protein needs of adults and children over one year.

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JANE O'HARA-MAY

of albumin he was left with the carbon present in nitrogen-free foods. Arbitrarily selecting starch and margarine84 as representative of the two nitrogen-free groups, Moleschott used their formulae, the ratio of fat to starch (1:4.84) from the dietaries referred to above and, making adjustments for respiration, calculated the amount of starch, fat and water taken in. He found by this method that the calculated total food intake was approximately the same as the dietary average: 3.818 kg compared with 3.448 kg. He took the similarity of the two results to be "the best proof that the food requirements we have given, as sufficient for a working man, are not exaggerated."85 This emphasis on the fact that the quantities he had advocated for a working man were not too large is found throughout his work. By comparing "active," "resting," and "subsistence" figures,86 Moleschott underlined the need of an active man for more than a minimal allowance. It may have been his emphatic belief in the necessity of proper nourishment for a man to work and a woman to feed her children which led him to formulate his standard. Moleschott himself gave no direct explanation, either in his Preface or in the relevant chapter of Physiologie, as to why he wished to show, against contrary opinion, that such a standard could be set up, but his approach would have been derived both from his work and from his philosophy. Moleschott's physiological investigations covered a wide field, including work on the kidney, blood, and respiration. The use he made of the many tables given in his publications illustrate the importance he placed on scientific measurement in nutritional work-an attitude he would have met when he worked briefly in Mulder's laboratory (1845)87 after taking his M.D. degree at Heidelberg. Returning to teach at Heidelberg in 1847, he did not confine his interests to laboratory research but included the study of man as a whole in his lectures. He was particularly concerned with the causes (chemi84. Margarine (margaric acid) was discovered by M. E. Chevreul in 1813. In 1855 W. H. Heintz described it as a mixture of palmitin and stearin. 85. Moleschott, Physiologie, p. 224. 86. Moleschott, Physiologie, p. 225. The "resting" figure was obtained from reports by Playfair on the diet of English and Bengalese prisoners (see n. 63 above). The "subsistence" figure (40 g albuminous material) was considered to be of interest only to scientists and perhaps those shipwrecked or beseiged. 87. See W. Moser, DeT Physiologe Jakob Moleschott (1822-1893) und seine Philosophie, Ziurcher Medizingeschichtliche Abhandlungen, Neu Reihe 43 (Zurich: Juris-Verlag, 1967).

268

Measuring Man's Needs cal and physical) rather than the reason (theological and philosophical) of man's being. The strength of these materialistic views caused such opposition that he was forced to leave Germany, and it is for his views in the philosophy of materialism88 rather than for his work in physiology that Moleschott is remembered today. His friend Ludwig Feuerbach, discussing Moleschott's Lehre der Narungsmittel fur das Volk (1850),89 summed up the content of the book with the oft-quoted comment: "der Mensh ist was er isst," 90 "man is what he eats." It was in this book that Moleschott made his most controversial and most quoted statement, namely, "Ohne Phospher kein Gedanke," 91 though these words have in fact been attributed to a variety of other authors, including Liebig.92 It can be seen that within the framework of his strong materialistic philosophy, the importance of a proper diet for the health, happiness, and fulfillment of man must have had a particular significance for Moleschott. As already noted, Moleschott was not alone in his attempts to quan.tify dietary needs. Several examples of similar approaches may be cited: Gasparin had pointed out the importance of both parts-the ration d'entretien and ration de travail-in a proper diet, when discussing the work of a farm laborer;93 the work of Hildesheim, already referred to; I. Leitch, in "The Evolution of Dietary Standards" written in 1942,94 commented particularly upon the standard set by Dr. Edward Smith95 in his report on the Lancashire Cotton Famine of 1862;96 the famous 88. Moleschott had eighteen references in the index of F. A. Lange The History of Materialism and Criticism of Its Present Importance, trans. E. C. Thomas, 3rd ed. (London: Kegan, Paul, Trench, Trubner & Co., 1925), three volumes in one. (lst German ed., 1865.) 89. J. Moleschott, Lehre der Nahrungsmittel fur das Volk (Erlangen: F. Enke, 1850). The book itself gives Erlangen as place of publication; some bibliographies quote Stuttgart. 90. Moser, Moleschott, p. 18. 91. Moleschott, Lehre der Nahrungsmittel, p. 116. 92. J. Liebig, Principles of Agricultural Chemistry with Special Reference to the Late Researches Made in England, trans. W. Gregory (London: Walton & Maberly, 1855), p. 49n. 93. Gasparin, in Cours d'agriculture, V, 390, suggested a total of 25.01 g nitrogen and 309.0 g carbon for a man weighing 62.541 kg. 94. Nutrition Abstracts and Reviews, 11 (1942), 509-521. 95. Great Britain, Public Health, Fifth Report of the Medical Officer of the Privy Council (London: Eyre & Spottiswoode, 1863), App. V, pt. 3 (Edward Smith, "Nourishment of the Distressed Operatives"), pp. 320-456. 96. Edward Smith (1818-1874) advocated 200 grains of nitrogen and 4,000 grains of carbon for a man's body weight of 150 lb (1 oz avoir = 437.5 grains).

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physiologist Karl Vierordt also provided quantities for required dietary intake.97 Of the figures available then as well as later, Moleschott's standard was the one most widely quoted. The reasons for this selection would seem to be due to the authority of the author in the subject, the place of publication, and the method of presentation. Though Moser suggests that Moleschott, in his own time, was counted in the second rank of scientists (partly perhaps through disapproval of his philosophy),98 the influential English writers E. A. Parkes, and G. E. Day, in 1864, described him, in relation to nutrition, as "the greatest authority at present" and "a well-known German [sic] authority on dietetics." 99 Moreover, Moleschott's standard was published in a book dealing specifically with nutrition. The figures of Gasparin, Smith, and Vierordt appeared in works of a different character. In the large number and wide range of his publications'00 Moleschott succeeded in his aim of describing the newest discoveries simply and clearly, so that they were comprehensible to an audience beyond just those who specialized in the subject. In contrast Hildersheim's work, though quoted by Parkes,10' required a persistent student to work through the tables, which had the weights given in "loths" to the fourth decimal place.102 The continued reference to Moleschott's "numbers" in textbooks will have been influenced by the usual habit of repetition and by the respect and affection in which Moleschott was held until the end of his life. Moser103refers to the greetings Moleschott received on his seventieth birthday (1892) from the most important men in Europe. The tributes paid him at that time by his Italian colleagues were published after his death in a translation of his autobiography.'04 97. K. Vierordt (1818-1884), Der Physiologie des Menschen (Frankfurt A.M.: Meidinger Sohn & Co., 1860), p. 192. 98. Moser, Moleschott, p. 7. 99. E. A. Parkes, A Manual of Practical Hygiene Prepared Especially for Use in the Medical Service of the Army (London: Churchill & Sons, 1864), p. 139. G. E. Day, Chemistry in Relation to Physiology, p. 514. 100. See Moleschott's Untersuchiungen zur Naturlehre des Menschen und der Thiere, ed. G. Colasanti & S. Fubini (Giessen: E. Roth, 1895), vol. XV, pt. I, pp. 12-20. 101. Parkes, Manual of Hygiene, p. 139. Here Hildesheim's figures are given in "ounces avoir" as: albuminates 4.64, fat 1.3, starches 16.8. 102. One Loth = approx. 1/32 - 1/30 of an ounce. The value varied at different times. 103. Moser, Moleschott, p. 27. 104. Elsa Patrizi-Moleschott (trans.), Jacopo Moleschott, Per gli amici miei: Ricordi autobiograftci (Milan, Palermo, Naples: Remo Sandron, 1902), pp. 291-350. Tributes came from D'Annunzio, A. Mosso, C. Lombroso, and P. Giacosa.

270

Measuring Man's Needs Finally, it is of interest to see how Moleschott's standard was used in the subsequent years of the century. Referring in 1862 to the calculations of requirements, the German physiologist Garup-Besanez commented that though Moleschott's calculations were based on partly unsure and variable data it should still give some idea of the actual state of affairs.'05 After further detailed comment on Moleschott's chapter, Garup-Besanez stressed that the calculations were valid only as far as they had been made on the results of a large number of people and were not applicable to individual cases. The writer, like others at that time, then concentrated on what the figures meant in terms of foods to be eaten.'06 This type of approach is also found in Pavy's Treatise on Food and Diet'07 of 1874 where specific reference is made to Moleschott's standard. For some workers the results of Ranke's experiment on himself'08 supplanted Moleschott's figures. Michael Foster, in his Textbook of Physiology (1878), quoted both Moleschott (inaccurately) and Ranke as follows:109 Moleschott Proteids Fat Amyloids Salts Water

30a [sic]

84 404 30 2800

Ranke (wt 74 kilos) 100 100 240 25 2600

aShould read 130 g. No units were given by Foster.

Here the weight of Moleschott's "reference man" was omitted, though Ranke's weight was given. Foster compared the two standards in the following terms: Of these two diets, which agree in many respects, that of Ranke is probably the better one, since in public diets, from which Moleschott's table is drawn, the cheaper carbohydrates are used to the exclusion of the dearer fats. 105. E. F. von Garup-Besanez (1817-1878), Lehrbuch der Physiologischen Chemie (Braunscweig: F. Vieweg & Son, 1862), pp. 749-751. 106. The characteristic modern approach of concentrating on the quantity of nutrients required without any immediate reference to foodstuffs was a later and a gradual development. 107. F. W. Pavy (1829-1911), A TTeatise on Food and Dietetics (London: J. & A. Churchill, 1874), p. 452. 108. J. Ranke (1836-1916), Grundzilge der Physiologie des Menschen (Leipzig: W. Englemann, 1868), p. 158. 109. M. Foster (1836-1907), A Textbook of Physiology (London: Macmillan, 1878), p. 358. (lst ed., 1877).

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In the fourth edition of Foster's Textbook (1884), he quoted the same figures (with Moleschott's proteids corrected), but under the headings "Public diet (Moleschott)" and "Ranke."110 In the fifth edition (1891) reference was made simply to diets 'A' and 'B,' with diet 'A' the same as Ranke's standard. In each case the energy value in calories had been calculated."' Despite the growing emphasis, at the turn of the century, on the energy value and mineral content, as well as the protein value, of diets, Moleschott's figures were still referred to by workers in many countries. In the United States, W. Gilman Thompson, in his Practical Dietetics of 1896, quoted Moleschott's standard in comparison with those of Pettenkofer (1819-1901) and Voit (1831-1908), Ranke, Playfair, Foster, Landois (18371902), and Du;ardin-Beaumetz (1833-1895),112 as well as referring to the quantity of "dry food" (23oz) advocated by Moleschott. This information was given in conjunction with advice from Letheby and Pavy."13The Frenchman Cathelineau and Lebrasseur, in Hygiene et regimes alimentaires of 1897, worked from the ration d'entretien of Voit and Pettenkofer,14 Moleschott's figures being given as a standard of comparison for soldiers' diets.11' Reference has already been made to the inclusion of Moleschott's figures in the table of standards given in the 1933 edition (9th) of Hutchinson's Food and the Principles of Dietetics. The table appears in the first nine editions of the work and includes the standards of Rubner and Atwater,'16 the leading workers in the field of human energy metabolism. In the 1930s this type of table disappeared, taking Moleschott's figures with it. The modern approach was developing. A number of national standards were put forward,"17 and in the mid-thirties the League of Nations attempted to collect information on nutritional conditions in many countries and formulated a general average standard in terms of energy, protein, calcium, and iron, pub110. Foster, Physiology, 4th ed. (1884), p. 446. 111. Foster, Physiology, 5th ed. (1891), II, 833. 112. W. Gilman Thompson, Practical Dietetics: with Special Reference to Diet in Disease (New York: Appleton & Co., 1896), p. 264. 113. Ibid., p. 269. 114. H. Cathelineau and A. Lebrasseur, Hygiene et regimes alimentaires (Paris: Rueff & Cie, 1897), p. 131. 115. Ibid., p. 173. 116. Max Rubner (1854-1932), W. 0. Atwater (1844-1907). 117. Examples are the Report of the Committee on Nutrition of the British Medical Association and H. K. Stiebling's figures (U.S. Department of Agriculture, Miscellaneous Publication no. 183), both published in 1933; also the Canadian Council on Nutrition's figures of 1939.

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Measuring Man's Needs lishing reports in 1936 and 1938.118 The impact of the Second World War, together with rapid advances in nutritional knowledge led the U.S. Food and Nutrition Board to prepare, in 1941,119 a carefully considered standard of dietary allowances built up from the specialized knowledge of many experts and providing a standard in terms of calories, protein, minerals, and vitamins for groups of the population according to age, sex, and activity. This "expert committee"approach is the one now favored for the preparation of national and international dietary standards. However, it was not until the first report of the United Nations Food and Agriculture Organization on Calorie Requirements,120 published in 1950, that a generally accepted standard was once more related to the body-weight of a reference man (and reference woman). When judging the importance of Moleschott's standard it is apparent from the lack of both contemporary and later comment that the significance of his method of calculation was overlooked. Nor can the number and long sequence of references to his figures be taken as a measure of their influence for, as we have seen, they were quoted uncritically, often inaccurately, and usually without any reference to the fundamental basis that Moleschott himself had laid down-i.e., the relation of food intake to the unit of body-weight and unit of time. Nevertheless, the standard was important for it was presented by a recognized authority at a time when the changing attitude toward quantification with respect to the health of the publicl'l permitted the acceptance of a quantified dietary standard. It provided a guide and a first stone for the foundation on which are formulated the nutritional needs of the world's population today. 118. League of Nations, Report of the Technical Commission on Nutrition, Quarterly Bulletin of the Health Organization, 5 (1936), 391-570; 7 (1938), 460-502. 119. U.S. National Research Council, Recommended Dietary Allowances (Washington, D.C.: National Academy of Sciences, 1943). 120. United Nations, Food and Agriculture Organization, Calorie Requirements, F.A.O. Nutritional Studies, no. 5, 1950. 121. This subject has been discussed by G. Rosen, "Problems in the Application of Statistical Analysis to to Questions of Health," Bulletin of the History of Medicine, 29 (1955), 27-45, and R. H. Shryock, "The History of Quantification in Medicine," Isis, 52 (1961), 215-237.

273

Concepts of Nerve Fiber Development, 1839-1930 SUSAN M. BILLINGS Department of Anatomy Harvard Medical School Boston, Massachusetts

In other sciences, one discusses only theories and hypotheses; in histology, one discusses facts as well as theories; it is for this reason that, in our domain, it is so difficult to triumph. The scientists who by dint of sagacity and perseverance manage to impose on general conviction the reality of a new fact, correctly interpreted, crown with success an undertaking whose difficulties escape the tranquil researchers in physics or chemistry. Ram6n y Cajal, 1909 -Santiago (introduction to Georges Marinesco's La Cellule nerveuse)

Nearly a century elapsed between the first modern description of the way a nerve fiber might develop and general agreement as to how this was accomplished. As early as 1839 Theodor Schwann attempted to explain the formation of nerves on the basis of microscopic observations of embryos. It was not until 1930, however, that most investigators agreed on a single concept of nerve fiber development, the so-called outgrowth theory. In the intervening period anatomists examined the embryonic and adult nervous system in a variety of animals, and their speculations on its development filled the contemporary journals. This was a problem that generated extraordinary interest and, almost inevitably, heated controversy. A number of elements, all interrelated, accounted for this relatively lengthy period of debate. Foremost, perhaps, were concepts of the structure of the nervous system. Late in the nineteenth century the dominant view of the nervous system was that a continuous network, or "reticulum," of anastomozing processes united all nerve cells. The nervous system was considered, in other words, to be a special type of cellular syncytium in which the nucleated centers were linked together by fibers.' 1. Described by Joseph von Gerlach, "The Spinal Cord," in Manual of Human and Comparative Histology, S. Stricker, ed., trans. from German by H. Power (London: The New Sydenham Society, 1872), II, 327-366. Journal of the History of Biology, vol. 4, no. 2 (Fall 1971), pp. 275-305.

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Santiago Ramon y Cajal2 presented evidence in 1889 that opposed this view. In studying material prepared with Golgi's technique, Cajal had found indications that a given nerve process was continuous with only one nerve cell. According to this idea, a nerve cell together with all its processes would comprise an independent unit, labeled a "neuron" by H. W. G. Waldeyer.3 Subsequently, however, this neuron theory was sharply attacked by a number of prominent histologists led by Stefan Apathy4 and Camillo Golgi,5 and during the first decade of the twentieth century the balance of opinion favored a reticular concept of the nervous system.6 In contrast, most other tissues were almost immediately recognized to consist of independent cellular units. It is therefore not surprising that many embryologists conceived of the development of the nervous system as following principles different from those they applied to other tissues,7 for they were attempting to explain the creation of an unusual and highly complex syncytium. A second factor that blocked an earlier understanding of nerve fiber development was the use of a purely observational method combined with equipment and techniques inadequate for the task. Although images provided by the Golgi and neurofibrillar stains had a profound influence on ideas of the way nerve fibers 2. Recollections of My Life (1901-1917), trans. from 3rd Spanish ed. by E. H. Craigie (Philadelphia: American Philosophical Society, 1937), pp. 355-357. 3. "Ueber einige neuere Forschungen im Gebiete den Anatomie des Centralnervensystems," Deutsche Med. Woch., 17 (1891), 1213-1218, 12441246, 1267-1269, 1287-1289, 1331-1332, 1352-1356. 4. "Das leitende Element des Nervensystems und seine topographischen Beziehungen zu den Zellen," Mitt. Zool. Stat. Neapel, 12 (1897), 495-748. and Facts" (1906) in Nobel Lectures: 5. "The Neuron Doctrine-Theory Physiology or Medicine, 1901-1921 (Amsterdam: Elsevier, 1967), pp. 189217. 6. A brief discussion of the histological basis for the controversy over the neuron theory is found in Alan Peters, Sanford L. Palay, and Henry de F. Webster,

The

Fine

Structure

of the

Nervous

System

(New

York:

Hoeber-Harper & Row, 1970), pp. 2-4. 7. The theory of development by cell division was proposed as early as 1845 by John Goodsir; see James Tyson, The Cell Doctrine: Its History and Present State (Philadelphia: Lindsay and Blakiston, 1870). This idea was subsequently accepted by all but a few investigators. Notable among the latter was Adam Sedgwick, who stated in the introduction to his 1894 paper, "Who, then, can deny that the cellular theory of development is still a living power in the school of biology? That it blinds men's eyes to the most patent facts, and obstructs the way of real progress in the knowledge of structure, it will now be my endeavour to show." ("On the Inadequacy of the Cellular Theory of Development, and on the Early Development of Nerves, Particularly of the Third Nerve and of the Sympathetic in Elasmobranchil," Quart. J. Micr. Sci., 37 [1894], 90.)

276

Concepts of Nerve Fiber Development were formed during the first decade of the twentieth century, it is now apparent that the issue could not have been settled by mere repetition of earlier studies using these methods. At that time a three-cornered debate had arisen. Supporters of the "multicellular" theories claimed that the formation of a nerve fiber required the participation of a number of cells. Those who subscribed to the "protoplasmic bridge" theory maintained, on the other hand, that a nerve fiber was formed in protoplasmic bridges that had originally connected all embryonic cells and were retained during development. A third group advocating the "outgrowth" theory stated that a nerve fiber grew forth from a single nerve cell into interstices between other cells. However, none of the groups could give conclusive proof of its own view, and the argument reached an impasse in which strong language tended to replace strong evidence. Ross Harrison's application of an experimental approach to this problem provided data obtained in a completely different way. His elegant experiments suggested clear answers to the questions of whether the growth of a nerve fiber required the presence of sheath cells or preformed protoplasmic processes, and were instrumental in laying the issue to rest. Thus obstacles created by contemporary concepts of the adult nervous system and by methods of examining its development were major factors in prolonging the debate over nerve fiber development. I will now discuss in turn each of the three major theories, outline data provided by the experimental approach, and attempt to show how general agreement was ultimately reached. OBSERVATIONALMETHOD 1. Multicellular Theory In 1839 Theodor Schwann8 published the Mikroskopische Untersuchungen in which he described, among many other things, the nerves of the fetal pig. After teasing these fibers apart under water, examining them microscopically, and comparing them with adult nerves he concluded: Nerves grow neither from the periphery toward the central organ nor from the central organ toward the periphery, but their primary cells are included with the cells from which every organ is formed and which, at least in their appearance, 8. Mikroskopische Untersuchungen uiber die Uebereinstimmung in deT Struktur und dem Wachsthum der Thiere und Pflanzen (Berlin: Sanders, 1839).

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are indifferent. They are first characterized as nerves when they line up in rows and fuse to form a secondary cell. After this coalescence each nerve fiber forms a separate cell that extends uninterrupted from the organ in which it terminates in the periphery to the central organ of the nervous system.9 This multicellular theory of the origin of nerve fibers was in accord with Robert Remak's'0 description of the nerves of young rabbits that had appeared three years earlier. Studying material prepared in the same way, Remak had found that the cerebrospinal nerves at an early age consisted of spheroidal corpuscles of varying dimensions that were arranged in rows. He stated that "a structureless, in general globular mass is the original form out of which the primitive fibers of the cerebrospinal nerves develop." 11 After Schwann the multicellular theory of nerve fiber development was not revised until a time when both tissue preparation techniques and the compound microscope were more highly advanced. When Francis Balfour12 examined the nerves of elasmobranch fish'3 in 1876, stained sections of fixed and embedded materials, most likely examined with a microscope employing a substage condenser, provided the basis for his conclusions. Like Schwann, Balfour believed that each nerve fiber arose from several primitive cells. However, the two men had a very different conception of the adult nervous system. Schwann had envisioned the adult nerve fiber as a single cell unconnected to ganglion-globules or other cells, while Balfour, in accord with the later observations of Remak,'4 Albert von Kblliker,'5 and others, believed that the fiber was continuous with nerve cells. 9. Ibid., p. 177. 10. "VorlIufige Mittheilung microscopischer Beobachtungen uber den innern Bau der Cerebrospinalnerven und uber die Entwickelung ihrer Formelemente,"Mullers Arch. Anat. Physiol. wiss. Med. (1836), 145-161. 11. Ibid., p. 153. 12. "On the Development of the Spinal Nerves in Elasmobranch Fishes," Phil. Trans. Roy. Soc. Lond., 166 (1876), 175-195; A Treatise on Comparative Embryology, II (London: Macmillan and Co., 1880-1881), 448-466. 13. As the lowest form classified among the true Vertebrata, Elasmobranchii were a favorite subject of study for embryologists. Balfour discusses some of the benefits of this comparative approach in the introduction to A Treatise on Comparative Embryology, I, 1-6. 14. "Anatomische Beobachtungen uber das Gehirn, das Ruickenmark und die Nervenwurzeln," Mullers Arch. Anat. Physiol. wiss. Med. (1841), 506-522. 15. Die Selbstandigkeit und Abhdngigkeit des sympathischen Nevernsystems, durch anatomische Beobachtungen bewiesen (Zurich: Meyer und Zeller, 1844).

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Concepts of Nerve Fiber Development Balfour suggested that in elasmobranchs rudiments of both the anterior and posterior roots of the spinal cord grew out from the epiblast of the central nervous system as a stream of undifferentiated embryonic cells. These subsequently developed into the adult dorsal nerve root, ganglionic cells, and nerve fibers. This observation overcame, in Balfour's opinion, the major difficulty of the hypothesis as it had previously been stated, namely: It never appeared clear how it was possible for a state of things to have arisen in which the central nervous system, as well as the peripheral terminations of nerves, whether motor or sensory, were formed independently of each other, while between them a third structure was developed which, growing in both directions (towards the centre and towards the periphery), ultimately brought the two into connexion.16 After Balfour's premature death at the age of thirty-one, many of his ideas were perpetuated in the theories of John Beard, Anton Dohrn, and Giovanni Paladino. Working independently, the first two investigators described similar events in the development of peripheral nerves in elasmobranchs. Beard'7 reported that dividing cells at the inner surface of the neural tube gave rise to two types of neural elements. Some of these formed ganglion cells; others formed cell chains that initially lay within the neuroepithelium. "These chains (i.e., their nuclei) proceed to secrete, from before backwards as fast as they are formed, nerve fibrils or axis-cylinders outside of themselves, and each linear row secretes one axis-cylinder . . . I look upon the nuclei of Ranvier's nodes . . . as those of nerveforming cells." 18 Beard thus believed the axis-cylinder to be the extracellular product of many cells that was formed in a proximal-to-distal direction. In 1891 Dohrn,19 basing his conclusions upon a study of the developing lateral line nerve, also suggested that cell chains of ectodermal origin formed primary nerves. He believed, however, that the axis-cylinder was formed within, rather than outside 16. Balfour, "On the Development of the Spinal Nerves" (1876), 190. 17. "Morphological Studies. II. The Development of the Peripheral Nervous System of Vertebrates. Part I. Elasmobranchii and Aves," Quart. J. micr. Sci., 29 (1888), 153-227; "The Histogenesis of Nerve," Anat. Anz., 7 (1892), 290-302. 18. Beard, "The Histogenesis of Nerve" (1892), 295-296. 19. "uber die erste Anlage und Entwicklung der Augenmuskelnerven bei Selachiern und das Einwandern von Medullarzellen in die motorischen Nerven," Mitt. Zool. Stat. Neapel, 10 (1891), 1-40.

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of, the protoplasm of these cells. Paladino20 extended the essentially similar theories of Beard and Dohrn to the central nervous system. The basic concepts of the multicellular origin theory were stated in the papers of Schwann, Balfour, Beard, Dohrn, and Paladino. Other investigators proposed that nerve fibers might be formed in a multinucleated syncytium that had at no time consisted of individual cells. Their hypotheses form an intermediate between the multicellular theory and Victor Hensen's protoplasmic bridge theory, which will be discussed in the next section. Adam Sedgwick2' concluded in 1894 that the nerves of elasmobranchs were formed from a protoplasmic reticulum that interconnected the three embryonic layers from the earliest stages of development. It was, he believed, secondarily invaded by nuclei that originated from the neural crest. The nerves were formed by a gathering up of strands of this reticulum into bundles, a process that proceeded from the medullary walls out toward the periphery in both the anterior and posterior roots. Three years after Sedgwick's paper, Stefan Ap6athy'sstudy of the nervous systems of the leech and earthworm appeared.22 It was one of the most influential papers written in this period. There seem to be two major factors that account for this. On the one hand, it was generally believed that study of simple lower animals would most clearly reveal basic developmental principles. Apathy's was one of the most complete early papers on any invertebrate nervous system. More important was the fact that Apathy had developed a modified gold chloride method that gave the first selective staining of neurofibrils. Previously, these elements had been vaguely outlined in certain cells by the staining methods that were commonly used to study nervous tissue, and it was generally thought that they might represent pathways for the flow of electric currents.23 Apa6thy'swonderfully detailed descriptions of the intricate fibrils within cells of the nervous system caused great excitement, for they seemed at last to define the structural basis underlying nervous conduction. 20. "De la continuation de la n6vroglie dans le squelette myelinique des fibres nerveuses et de la constitution pluricellulaire du cylindraxe," Arch. ital. Biol., 19 (1893), 26-32. 21. Sedgwick, "On the Inadequacy of the Cellular Theory of Development" (1894). 22. Apathy, "Das leitende Element" (1897). 23. Electrical phenomena in active nerves were described as early as 1843 by Emil du Bois-Reymond in "Vorlaufiger Abriss einer Untersuchung Froschstom und uber die elektromotorischen uber den sogenannten Fische," Ann. Phys. Chem., 58 (1843), 1-30.

280

Concepts of Nerve Fiber Development Specifically, Apathy was convinced that the nervous systems of the invertebrates he had studied were composed of two cellular elements, nerve cells and ganglion cells. The nerve cell, he believed, formed the elementary fibrils that were grouped together as a single neurofibril extending into a process of the cell. This neurofibril passed through a number of ganglion cells, which served as batteries supplying the energy that was conducted along the fibril. With this purely electrical concept of the functioning nervous system, the item of chief importance in development was determining where the neurofibrils were laid down. According to Apaithy, this took place in the cell net that he thought linked all embryonic cells. In whole mounts of the skin of amphibian larvae fixed in an osmium bichromate solution and stained with hematoxylin, Oskar Schultze24 claimed to have visualized a multinucleated syncytium within which he believed the future nerves would be differentiated. He too suggested that this syncytium was formed by the maintenance of intercellular bridges resulting from incomplete cytoplasmic cleavage (cytokinesis) following nuclear division. Albrecht Bethe25 believed that the primary cell net was formed specifically in areas of future nerve development. Studying chick embryos, he demonstrated long rows of nuclei extending between the spinal cord and periphery that had been formed, he claimed, by repeated mitosis. Around these, protoplasm condensed to form a syncytium. Axis cylinders that subsequently contained fibrils were formed by condensation, which occurred in wave-like fashion in the territories of abutting nerve cell nuclei.26 The latter continued to divide during this formative period. The nerve cell nuclei ultimately became smaller in size and were converted into the nuclei of Schwann. Unlike other investigators, Bethe believed that one primary cell row could form more than one nerve fiber. Of the three basic hypotheses proposed to explain nerve fiber development, various forms of the multicellular theory were by far the most popular in the years 1890-1910. This was due 24. "Beitrage zur Histogenese des Nervensystems. I. tuber die multizellulare Entstehung der peripheren sensiblen Nervenfaser und das Vorhandensein eines allgemeinen Endnetzes sensibler Neuroblasten bei Amphibienlarven," Arch. mikr. Anat., 66 (1905), 41-110. 25. Allgemeine Anatomie und Physiologie des Nervensystems (Leipzig: Thieme, 1903). 26. Note the similarity between this description of protoplasmic condensation around a nuclear core and Schwann's concept of the way in which tissues developed.

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largely to the impact of Ap6athy'swork.27 A few investigators even continued to cling to the theory despite the experimental and observational evidence against it that had become available by 1920. The decline in popularity of this concept will be considered in more detail after the competing ideas have been described. 2. Protoplasmic Bridge Theory Victor Hensen28 studied the development of nerves in the tail of the tadpole. On the basis of his observations on this and other embryonic nervous tissue prepared by hardening in acidic solutions and hand sectioning, he proposed the protoplasmic bridge theory of nerve development: I wish to submit here for consideration another type of nerve development that turns out to be a possibility. It could be that the terminal cell of the nerve is at no time separated from the nerve's ganglion

of origin, i.e., that . . . the first

cells of the spinal cord are not fully separated from one another but always remain in contact with each other by means of a thread, the nerve. This idea is not so completely fantastic as it would seeml To demonstrate that this is the case, I wish to follow through its reasoning. If we arbitrarily designate the beginning of the axial-plate or primitive groove as the origin of these processes, then we would agree that from this time-point on cell divisions in the axial-plate would not go to completion, but rather each cell would remain in contact with its sister cell. However, we assume that when this cell divides again it also cleaves its binding cord more or less completely. This last assumption that the nerve can be cleaved may provoke doubt; however, it is wholly necessary when we consider the growth of nerves, for with the growth of the tail and the increased number of end-apparatuses it would be reasonable to also expect a division of nerve fibers. The divided nerves move apart with time, an event that is sufficiently explained by the growth ratio of the whole parenchyma. If then each part is imperfectly separated this process results eventually, as one easily sees, in an infinite network of fibers. If I assume that of this network only 27. See, for example, the discussion by Lewellys F. Barker in The Nervous System and its Constituent Neurones (New York: D. Appleton and Co., 1899), pp. 52-65. 28. "Ueber die Entwickelung des Gewebes und der Nerven im Schwanze der Froschlarve," Virchows Arch. path. Anat., 31 (1864), 51-73.

282

B

^

ms

~~~~~9

p.~~~~~~

2

;

nf

"~f4

thr

34 hours

Above, left. Ram6n y Cajal's drawing of a nerve cell with its growing axon, stained by the Golgi method. The growth cone (c) at the tip of the fiber can be seen to bristle with lateral wing-like excrescences. From Histologie du systeme nerveux, fig. 240. Above, right. Hans Held's drawing of the growing tips of cutaneous nerves in a tadpole fin, stained with molybdenum-haematoxylin. At the left, the single arrow indicates the passage of part of a forked nerve tip into the pale stained Plasmodesmen. The arrows at the right show the transverse section of a thick neurofibril located within a protoplasmic process. From Die Entwicklung des Nervengewebes, fig. 195. Below. Ross Harrison's drawing of a living specimen of embryonic tissue isolated in clotted lymph. It shows four nerve fibres (nfl-nf4) growing from the mass of tissue (ms) at the left. PI indicates the protoplasmic tip (growth cone) of fiber nf4. The only solid structures present in the culture near the ends of the growing fibers are threads of fibrin (thr). (Ct1 and ct2 are motile embryonic cells.) From "The Outgrowth of the Nerve Fiber" (1910), fig. 9.

Concepts of Nerve Fiber Development those fibers remain behind and are preserved that are useful for the body and will be utilized, while the inactive pathways atrophy, then this theory could be spoken of as a natural and acceptable point of view. Together with the above it is in accord with what we know of the arrangement of the nervous system.29 Perhaps the most appealing aspect of Hensen's theory was his idea that the adult nervous system was formed from those embryonic conducting pathways that were actually used. Those that were unused simply disappeared. Hensen suggested, in other words, that the patterning of adult nerve fibers was the result of adaptation to needs imposed by the body. This was in accord with other observations of structural modifications occurring during the lifetime of an animal. It was known, for example, that if muscles were used vigorously and often they usually became larger and stronger, while paralysis resulted in a marked reduction in muscle size. Thus the logical basis for at least part of Hensen's hypothesis seemed firm. In 1868 Hensen30 reiterated his idea that embryonic conduction paths were pulled out by the gradual separation of cells and tissues from one another during development. Certain of these paths were subsequently converted into adult nerve fibers. He stated that this hypothesis was probably not exactly correct because of the impossibility of reconstructing natural events flawlessly. However, he believed that it was the only valid explanation then available for the orderly distribution of nerves, assuming one did not appeal to a "Spiritus rector" that guided nerve fibers growing into a tissue. Hensen dismissed growth of nerve fibers into tissues on more than theoretical grounds. No investigator had even demonstrated outgrowing nerve tips, he stated, and his careful examination of tadpole tails had failed to reveal their presence. Hensen's theory was never as popular as the multicellular theory. This was probably due to the fact that only small portions of Hensen's hypothesis bore a direct relationship to the observations he had reported, while most of the salient points were wholly a matter of conjecture. Yet, as we have seen, certain aspects were incorporated into the hypotheses of Ap6athy and other proponents of a modified multicellular theory. More important, however, was Hensen's influence on Held, which will be discussed in the next section. 29. Ibid., pp. 67-68. 30. "Ueber die Nerven Anat., 4 (1868), 111-124.

im Schwanz

der Froschlarven,"

Arch. mikr.

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3. Outgrowth Theory Friedrich Bidder and Carl von Kupffer31were among the first to suggest that axis cylinders grew out from embryonic nerve cells as direct processes. In accordance with this view, they stated that connective tissue and sheath-forming cells were secondarily applied to the young nerve fibers. In 1857 the development of nerves in the spinal cord of sheep and chicken embryos was summarized by Bidder and Kupffer: . . .in very early development the axis-cylinder grows from the embryonic nerve cell as a direct extension. It very rapidly attains the extent that corresponds to the length of the fiber into which it is predestined to enter at the end of development. After the white matter of the spinal cord and the spinal nerves are constructed from these elements, a blastema in which new cells arise comes to exist between the axis-cylinders. These new cells have a double destiny. On the one hand they form the loose interstitial connective tissue that is always found where nerve fibers lie together in bundles, while on the other hand, especially in peripheral nerves, they are converted to the formation of the primitive nerve sheaths isolating individual axis-cylinders. The sheath would thus be a secondary structure and one would look for the continuation of the nerve cell membrane along the axis-cylinder on which, as in the cell itself, membrane and content are fused into a homogeneous mass.32 The outgrowth theory was extremely difficult to rationalize with the contemporary conception of the adult nervous system as a network of anastomatic processes and, chiefly for this reason, it was not given serious consideration at the time it was first proposed. Twenty-nine years later Wilhelm His33 described the development of nerve fibers in human embryos that had been fixed, serially sectioned, and stained by several dye methods. He concluded his 1886 paper with the following: As a matter of established principle I state: that every nerve fiber issues as an extension from a single cell. This cell is its 31. Untersuchungen jiber die Textur des Riichenmarks und die Entwickelung seiner Formelemente (Leipzig: Breitkopf u. Haertel, 1857). 32. Ibid., p. 117. 33. "Zur Geschichte des menschlichen Riickenmarks und der Nervenwurzeln," Abh. math.-phy. Cl. Konigl. Sachsischen Ges. Wiss. (Lpz.), 13 (1886), 479-513.

284

Concepts of Nerve Fiber Development genetic, nutritive and functional center; all other connections of the fiber are either only indirect or have arisen secondarily.34 Earlier in the paper he had described the way in which nerve fibers grew in intercellular spaces. In the brain and spinal cord he believed that a primary stroma formed a sort of road-bed for growth, while in the periphery nerve fibers pushed their way through connective tissue components. He commented that the growth of these fibers was along paths of least resistance. In a later paper he discussed this point in more detail, stating, "an outgrowing nerve moves forward in the direction of its terminal sector as long as the way is not obstructed by some resistance. Blood vessels, cartilage or, in general, thickened areas in the tissue can turn the nerve aside from its course." 35 His believed that outgrowth was dependent solely upon the nerve cell, and that any nuclei seen in the region of developing nerve fibers belonged to parablastic cells, which were not directly involved in this process. He recognized an important implication of this mode of nerve fiber formation, namely, that there need not be continuity between the nerve fiber and the part innervated, be it a peripheral end-organ or another nerve cell. He stated, it would suffice if the off-shoots of reciprocal terminal stumps [were found] in the same region of myelin and [that there occurred] the intercalation of a stimulus-transmitting intermediary material." 36 Evidently His did not find any conflict between the apparent randomness in the way that he believed the nervous system to be formed and the reproducibilty of the structure and function of the adult nervous system.37 However, it was probably this factor that led to rejection of the outgrowth theory by many of His's contemporaries. Equally involved, perhaps, was the boldness with which His extended his theory into areas then impossible to study. It required the repeated efforts of other investigators, notably Ramon y Cajal, before even the plausibility of this theory was acknowledged. The successful application of a new staining technique was responsible for the single most important observation supporting 34. Ibid., p. 513. 35. Wilhelm His, "Die Entwickelung der ersten Nervenbahnen beim menschlichen Embryo. Uebersichtliche Darstellung." Arch. Anat. Entwickl.Gesch. (1887), 376. 36. His. "Zur Geschichte des menschlichen Riickenmarks" (1886), 512. 37. Wilhelm His, "Zur Geschichte des Gehirns sowie der centralen und peripherischen Nervenbahnen beim menschlichen Embryo," Abh. math.phy. Cl. Konigl. Sachsischen Ges. Wiss (Lpz.), 14 (1888), 341-392.

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the outgrowth theory. In 1873 Camillo Golgi38had published a paper on the structure of the gray matter of the brain. In it he reported new observations on nerve cells and processes that were largely the result of studying material prepared by immersing fresh tissue in a solution of potassium bichromate followed by silver nitrate. This method resulted in the intense black or reddish-brown coloring of an occasional entire nerve cell and its processes, clearly revealing its external form against a yellow background. In later studies,39 Golgi devoted considerable space to a discussion of the practical aspects of this method. It is perhaps not surprising that despite these efforts the new stain, which impregnated only a few rather than all cells and was championed by a little-known Italian investigator, did not receive serious consideration. Cajal wrote in his autobiography: . . .the admirable method of Golgi was then (1887-1888) unknown to the immense majority of neurologists or was undervalued by those who had the requisite information about it. Ranvier's book,40 my technical bible of those days, devoted to it only a few lines of description written so as to discourage interest. It is abundantly clear that the French savant had not tried it. Naturally, those, like myself, who relied upon Ranvier thought that the said method was not worth bothering about. The Germans41 manifested a similar disdain.42 In 1887 Luis Simarro first showed Cajal well-prepared sections made by Golgi's method and called his attention to Golgi's paper of 1885.43 The young Spaniard, highly excited by the possibilities of the method, immediately began work to modify its rather capricious and uncertain nature. Cajal first published studies on the structure of the adult nervous system based on a modified Golgi technique in 1888. In 189044 he described the results 38. "Sulla sostanza grigia del cervello," Gazz. Med. Lombarda, 6 (1873), 244-246. 39. Camillo Golgi, "Sulla fina struttura dei bulbi olfattorii," (1875) in Opera Omnia, I (Milan: Hoepli, 1903), 113-132; "Sulla fina anatomia degli organi centrali del sistema nervoso. IX. Metodi di indagine," Riv. sper. Freniat., 11 (1885), 193-220. 40. Louis-Antoine Ranvier, Traite6 technique d'histologie (Paris: Librairie F. Savy, 1875-1882), p. 1062. 41. One exception seems to have been K6lliker, who enthusiastically commented that Golgi's method was unsurpassed for demonstrating the nerve cell and its processes in "Die Untersuchungen von Golgi uber den feineren Bau des zentralen Nervensystems," Anat. Anz., 2 (1887), 480-483. 42. Ram6n y Cajal, Recollections, pp. 306-307. 43. Ibid., p. 308. 44. Santiago Ramon y Cajal, "A quelle epoque apparaissent les expansions des cellules nerveuses de la moelle 6piniere du poulet?" Anat. Anz., 5 (1890), 609-613 and 631-639.

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Concepts of Nerve Fiber Development of Golgi impregnations of spinal cords of chick embryos, beginning at the fourth day of incubation. Cajal examined a group of fibers that emanated from neuroblasts lying near the dorsal surface of the spinal cord and ran ventrally, ultimately decussating in the ventral commissure, and reported: Each fiber of this commissural fascicle terminates at a variable distance, proportional to its degree of development. The terminal structure is a conical swelling studded with very irregular spiny processes. This terminal swelling, which we call the growth cone, clearly demarcates the extremity of every developing nerve fiber. Moreover, one can recognize it very well, in silver chromate impregnations, by the brown or chestnut color of the small spiny processes which adorn its surface. Sometimes the growth cone possesses long triangular, lamellated, occasionally branched prolongations which seem to wind among the neural elements while making their way through the interstitial substance.45 This Golgi study revealed, for the first time, a structure that could reasonably be called the end of a growing nerve fiber. His's drawings of preparations made with dye stains had shown ends of developing nerve fibers that were identical in size and structure to more proximal parts of the fiber. The existence of these blunted processes neither confirmed nor denied the outgrowth theory since they were most likely formed by cutting the fibers during sectioning.46 One factor that convinced Cajal he had visualized the true end of the growing fiber was the similarity between the growth cone and the primitive terminal arborization that the fiber made when it contacted its target. Since Cajal considered the latter to be a specific and highly complex structure, its shape could most easily be explained if it had been formed in the neuroblast and subsequently pushed forth to its point of connection. Part of His's original hypothesis had been the suggestion that nerve fibers grew along paths of least resistance. In 1893 Cajal47 proposed that perhaps the nerve fiber was directed toward its goal by substances secreted by the future terminal cells of that fiber, and that the growth cone might be the part of the fiber 45. Ibid., p. 611. The translation is by Lloyd Guth and is taken from Cajal, Studies on Vertebrate Neurogenesis (Springfield: Thomas, 1960), p. 219. 46. Santiago Ram6n y Cajal, Textura del Sistema Nervioso del Hombre y de los Vertebrados (Madrid: Moya, 1899). 47. "La Retine des vert6br6s," Cellule, 9 (1893), 121-255.

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that was specifically sensitive to these materials. Cajal found this theory of chemotaxis more satisfactory than His's earlier contention, although he could find no reasonable way of proving it.4 Visualization of the end of a developing nerve fiber, the growth cone, was the single most important observation that supported an outgrowth theory. Subsequent to Cajal's first description a number of other investigators also examined Golgi preparations of embryonic material. In 1892 Mihaly von Lenhossek49 confirmed the existence of growth cones similar to those Cajal had described at the free ends of growing motor fibers in an elasmobranch fish. A year later Gustaf Retzius50 described identical structures at the tips of motor fibers of the chick as well as a variant in which a long, thread-like process seemed to precede the growth cone proper. Retzius also found that from neuroblasts that lay in a more dorsal part of the spinal cord there grew fibers that ended in cones of quite varied size and form. Some of these were of considerable volume and had a leaf-like ribbed and branched appearance. The latter were quite unlike any cones that had previously been described, although a similar staining method had been used. In his book on the structure of the nervous system Lenhossek5' described growth cones at the ends of commissural fibers in the spinal cord of the chick as roughened expansions that ended in triangular or spindle-shaped thickenings. In general these did not appear to be smooth, but were covered with tiny pointed expansions. He envisioned this pointed protoplasmic mass as 48. The term "chemotaxis" was used in 1884 by Wilhelm Pfeffer to describe the way in which the spermatozoids of ferns were attracted to the oospheres ("Locomotorische Richtungsbewegungen durch chemische Reize," UnteTs. Bot. Inst. Tiibingen, 1 [1881-18851, 363-482). The idea was soon extended to vertebrate cells, and a number of investigators described chemotaxic properties of leucocytes (G. Gabritchevsky, "Sur les propriet6s chimiotactiques des leucocytes," Ann. Inst. Pasteur, 4 (1890) 346-362; J. Massart and C. Bordet, "Le Chimiotaxisme des leucocytes et l'infection microbienne," Ann. Inst. Pasteur, 5 (1891), 417-444). :lie Metchnikoff was one of the first to suggest that chemotaxis might serve as an orienting factor during development. In 1892 he postulated that endothelial cells of developing capillaries possessed a chemotaxic sensibility that enabled them to contact each other and thus form new vascular loops (Lecons sur la pathologie compar6e de l'inflammation [Paris: Libraire de l'Acad6mie de Medecine, 1892], p. 225). 49. "Beobachtungen an den Spinalganglien und dem Riickenmark von Pristiurusembryonen," Anat. Anz., 7 (1892), 519-539. 50. "Zur Kenntniss der ersten Entwicklung der nervbsen Elemente im Ruckenmarke des Huhnchens," Biol. Unters., 5 (1893), 48-54. 51. Der feinere Bau des Nervensystems im Lichte neuester Forschungen (Berlin; Fischer, 1895).

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Concepts of Nerve Fiber Development working its way between other tissue elements by a sort of ameboid movement. Lenhossek pointed out that Cajal had earlier described the growth cone as a rudimentary terminal arborization.52 This, he felt, was an indication that the so-called growth cone was in reality a constant structure of a nerve fiber that formed at the cell of origin and advanced into the periphery. If this were the case, he argued, then it would be difficult to imagine growth as occurring by the apposition of material to the growth cone, for under these circumstances the integrity of its structure would soon be lost. Instead, Lenhossek found it more reasonable to consider that growth occurred internally by the incorporation of new materials either from the environment or from the cell body. On the basis of regeneration studies he favored the former view, although he believed that influence of the cell of origin was necessary of this uptake. Marck Athias,53found growth cones in the developing cerebellum of several small mammals. He described them, for example, at the ends of granule cell axons at a time when the cell body still resided in the molecular layer. He discussed in detail the development of mossy fibers, and stated that these fibers grew into the granular layer by means of a succession of growth cones that appeared at the extreme tips of the fibers. In the 1909 revision of Textura del Sistema Nervioso, Cajal54 reviewed his ideas on the structure and function of the growth cone. He described Golgi-stained growth cones within the central nervous system: Ordinarily the cone is somewhat flattened from top to bottom while it passes through the gray matter, and its edges appear bristling with little wings or lamellar appendages that are sometimes crossed by indentations. Because of their extreme thinness, these little wings appear to be colored bright brown in silver chromate preparations. At its very base, that is to say at the large end of the cone, it is not unusual to observe a longer membranous prolongation forming a sort of protoplasmic spur insinuated into the interstices of the cells or of the epithelium. Finally, one sometimes observes cones that are extremely flattened and look like membranes de52. Cajal, "A quelle epoque apparaissent les expansions des cellules nerveuses" (1890), 637. 53. "Recherches sur l'histog6n6se de l'6corce du cervelet," J. Anat. (Paris), 33 (1897), 372-404. 54. Histologie du systeme nerveux de l'homme et des vertbr6s, (1909), vol. I, trans. from Spanish into French by L. Azoulay (Madrid: Consejo Superior de Investigaciones Cientificas, 1952), pp. 597-601.

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lineated by ridges or ribs; the whole structure suggests the appearance of the foot of a palmiped.55 As mentioned previously, Ap6athy had achieved selective staining of invertebrate neurofibrils in 1897. Shortly thereafter Bethe56 developed a molybdenum-toluidine blue method that demonstrated these elements in the vertebrate. Both these staining methods were complex and tedious, and had a tendency to work well only in the laboratories of their inventors. In 1903 and 1904 Cajal57 and Max Bielschowsky58 introduced more reliable neurofibrillar stains based on silver salts, and armed with these two methods a number of investigators re-examined the growth cone. When stained by neurofibrillar methods utilizing reduced silver nitrate, Cajal59 and others found that the growth cone lacked the appendages and lateral excrescences previously described. It seemed merely to possess a central fibrillar core. On the basis of this histological dissection Cajal defined two parts of the cone, one neurofibrillar (the core) the other neuroplasmic (the lateral wing-like extensions). Sometimes the growth cone had an enlarged base within which rounded protoplasmic masses, or vacuoles, gave the false impression of holes running through the structure. Cajal interpreted this image as representing a cone whose progress had been partially obstructed. He believed that when the cone took the form of a huge mass, this indicated that growth of the fiber had been totally blocked. He did not, however, suggest that the material he found accumulated in the distal part of such a fiber was responsible for the lengthening of that fiber under normal circumstances. Cajal described the functions of the growth cone in the following way: . . . the growth cone is a sort of mace or battering ram endowed with an exquisite chemical sensitivity, rapid ameboidal movements and a certain propelling force, which 55. Ibid., p. 598. 56. "Das Molybdanverfahren zur Darstellung der Neurofibrillen und Golginetze im Centralnervensystem," Z. wiss. Mikr., 17 (1900), 13-35. 57. "Un sencillo m6todo de coloraci6n selectiva del reticulo protoplasmico y sus efectos en los diversos organos nerviosos. I. Mktodo tecnico," Trab. Lab. Invest. Biol. (Madrid), 2 (1903), 129-142; "Algunos metodos de coloraci6n de los cilindros-ejes; neurofibrillas y nidos nerviosos," Trab. Lab. Invest. Biol. (Madrid), 3 (1904), 1-7. 58. "Die Silberimpragnation der Neurofibrillen," J. Psychol. Neurol. (Lpz.), 3 (1904), 169-189. 59. Histologie du systQme nerveux, pp. 598-599.

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Concepts of Nerve Fiber Development permits it to push aside or cross over the obstacles erected in its path and thus force a passage for itself in the cellular spaces until it arrives at its destination. With respect to the protoplasmic appendages that crown this conical thickening, they are rudiments of the terminal arborization of the nerve.60 From the preceding descriptions it becomes apparent that early workers grouped under the heading of "growth cone" structures involved in two different types of activity. Both the structure occurring at the end of a fiber in transit and that terminating a fiber which had reached its goal and was beginning to form synapses were considered together. For example, structures that Athias described at the tips of mossy fibers growing in the granular layer of the cerebellum were almost certainly involved in synaptogenesis. On the other hand, those Retzius described at the tips of motor fibers found in the connective tissue space outside the brain were involved solely in growth. Cajal repeatedly emphasized the unity of structure of the growth cone and the rudimentary terminal arborization. To him, it provided another justification for the outgrowth theory. Today, however, it seems more reasonable to look upon these two structures as reflecting growth processes that differ in a number of ways. With the description of the growth cone, the outgrowth theory of His and Cajal was placed on much firmer ground. However, it was by no means the most popular theory of nerve fiber development at the turn of the century. As mentioned previously, contemporary views on the neurofibril were responsible, in large measure, for the overwhelming support accorded the multicellular theory. After the first enthusiasm over neurofibril had waned, however, investigators again aligned themselves in support of essentially the same multicellular, protoplasmic bridge or outgrowth theories. Despite the generally low status of the outgrowth theory, Cajal won for it the support of Albert von Kolliker, the patriarch of German histology and one of the most powerful biologists of the time. In a paper on the development of the elements of the nervous system published shortly after his death in 1905, Kolliker6l defended the outgrowth theory. He emphasized that nerve fibers in the central nervous system and in the periphery were formed as outgrowths from single cells. Their development required at no time the participation of more than one cell. 60. Ibid., pp. 599-600. 61. "Die Entwicklung der Elemente des Nervensystems," 82 (1905), 1-38.

Z. wiss. Zool.,

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It becomes obvious from reading this paper and one by Cajal62 on the development of nerve fibers that the methods beimg employed at that time were not yielding further new information that would resolve the debate over how nerve fibers were formed. In different hands the same staining technique gave varied results, and who could say which observations were correct? Even more unsatisfactory was the state of affairs in which two brilliant investigators studying almost identical material could disagree violently on what they were actually seeing. The conflict that arose between Cajal and Hans Held clearly demonstrated the need for a new method to study the development of the nerve fiber and brought to a close the era of a purely observational approach to neuroembryology. Held63 believed that nerve fibers always formed within the anastomotic processes of other cells. He used the word Plasmodesmen to describe the intercellular bridges that he found between processes of stellate cells or Leitzellen (potential Schwann cells) in the periphery. In the central nervous system he believed the processes of spongioblasts were interconnected in a similar way. Neurofibrils, according to Held, were formed in the soma of the nerve cell and grew out into the delicate conducting reticulum. At the tip of the growing fibrillar bundle was a structure that in Cajal's reduced silver stain appeared as a simple point, as though it were formed by a single neurofibril; occasionally it would end in a small, rounded blob. Held also found cases in which the fiber ended in a round thickening from which emanated a fine granulated fibril. Sometimes the terminating fibrils seemed to flay out into a tassel-like arrangement or form an anastomotic network. Held believed that all these terminal elements were comparable to what Cajal had earlier described as a growth cone.64 Held emphasized that the advancing tip of the neurofibrillar process always was found within some sort of lightly stained protoplasmic veil. The primary nerve process "advances not as 62. "Genesis de las fibras nerviosas del embrion y observaciones contrarias a la teoria catenaria," TTab. Lab. Invest. Biol (Madrid), 4 (1905), 227-294. 63. "Die Entstehung der Neurofibrillen," Neurol. Cbl. (Lpz.), 24 (1905), 706-710; "Zur Histogenese der Nervenleitung," Verh. anat. Ges. (Jena), 20 (1906), 185-205; "Kritische Bemerkungen zu der Verteidigung der Neuroblasten und der Neuronentheorie durch R. Cajal," Anat Anz., 30 (1907), 369-391; Die Entwichlung des Nervengewebes bei den Wirbeltieren (Leipzig: Barth, 1909). 64. Held, Die Entwicklung des Nervengewebes, pp. 20-22 and accompanying figures.

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Concepts of Nerve Fiber Development His suggests freely into any gap in any tissue; rather it pushes forward into the intercellular bridges or cell body of a second cell, into the framework of the marginal zone or finally, if it is a peripheral nerve, into the Plasmodesmen to the most distant regions of the embryo." 65 He believed that fibrils were formed in a special fibrillogenic area of the neuroblast's soma, and that they subsequently gathered together to form the nerve fiber. Presumably the propulsion of the bundle through the guiding syncytium was a consequence of the fibrils being formed in, and subsequently squeezed out of, this area. Held thought that later the neurofibrils merged to form a continuous network. In many respects Held's ideas seem related to those of Hensen. It is probably fair to say that both theories take common origin in an idea stated much earlier by Karl von Baer.66Namely, it was incomprehensible that a nerve process would be able to grow freely to its proper destination; rather, some connection must have always existed between the points of origin and termination of the nerve that was subsequently utilized in its formation. However, the importance Held placed upon the neuroblast's being the sole source of neurofibrils and upon the outgrowth of the fibrillar bundle also brought him into agreement with many of His's suggestions. Held upheld a reticular theory of the fully formed nervous system, for he believed that the fibrils interconnected all parts of the nervous system. However, the major point at which Cajal and Held differed in discussing the developing nervous system was whether the nerve process was (1) a neurofibrillar bundle that grew within the interconnected protoplasmic processes of other cells, that is, within Plasmodesmen, or (2) a membranelimited cytoplasmic element containing a neurofibrillar skeleton that grew out freely into extracellular spaces. Cajal67claimed that 65. Held, "Zur Histogenese der Nervenleitung" (1906), 188. 66. "That nerves grow from developing muscle or other parts into the central parts is to me at least equally unlikely as the converse, since this sort of development of any part continually from one end to the other so that one end receives new attachments has nowhere come to my attention. Rather, each part appears to be already there in toto from the beginning and to develop from within itself. Accordingly it is probable that as soon as there is adequate differentiation in abdominal plates or other parts whereby the nerve substance is divided from other substance be it only the lowest degree of differentiation, the nerve is present in its entire length and has both ends, the central as well as the peripheral." (Uber Entwickelungsgeschichte der Thiere, I [Konigsberg: Borntrager, 18281, 110.) 67. "Nouvelles observations sur l'evolution des neuroblastes, avec quelques remarques sur l'hypothbse neurog6n6tique de Hensen-Held," Anat. Anz., 32 (1908), 1-25 and 65-87.

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Plasmodesmen were artifacts of Held's preparative method, while Held,68 in turn, thought perhaps pale staining or alcohol fixation prevented Cajal from seeing them. The impression one might get from reading their papers is that Cajal and Held were discussing vastly different material. Yet Cajal added the following note to his completed 1908 paper: During a recent trip to Germany, we had the pleasure of examining Held's excellent preparations. Just as we expected, they are very successful, and to our great surprise, they show very much the same picture as ours.69 Thus Cajal and Held were unable to agree on what they saw in almost identical preparations. With a hint of weary irritation Cajal commented in 1909 that whereas in other sciences only theories and hypotheses were discussed, in histology one debated facts as well as theories.70 The conflict between Cajal and Held was symptomatic of the problem that faced investigators studying nerve fiber development. The purely observational approach simply was not sufficient to resolve the differences among the proponents of each of the three principal theories. Ross Harrison's bold application to the developing nervous system of experimental techniques pioneered by Wilhelm Roux7' provided the new information that was so desperately needed. Basically the experimental approach has two parts. The first is the formulation of a question whose answer would enable the investigator to choose between two hypotheses. The second is the designing of an experimental situation that will give an unequivocal answer to the question. From 1904 to 1924 Harrison and other investigators concentrated their efforts on answering the following questions: (1) does the growth of a nerve fiber require the presence of sheath cells and (2) does the growth of a nerve fiber occur only in areas that were in some way prepared for it in advance? It is fortunate that so ingenious and articulate an investigator as Harrison became the unofficial spokesman of the experimental method. It should be pointed out, however, that others like Hermann Braus also began to use a similar approach in studying the developing nervous system, and that 68. Held, "Kritische Bemerkungen" (1907), 372-373. 69. Ram6n y Cajal, "Nouvelles observations sur l'evolution des neuroblastes" (1908), 3. Translation by Guth in Studies on Vertebrate Neurogenesis, p. 72. 70. Ram6n y Cajal, introduction to Georges Marinesco, La Cellule nerveuse (Paris: Doin, 1909), I, 13-14. 71. For discussion, see Hans Spemann, Embryonic Development and Induction (New York: Hafner, 1962).

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Concepts of Nerve Fiber Development the investigation of nerve regeneration using lesions was already under way. EXPERIMENTALMETHOD 1. Does the Growth of a Nerve Fiber Require the Presence of Sheath Cells? In 1904 Harrison72 published the results of a study in which, for the first time, an experimental method was brought to bear on the problem of peripheral nerve development. In these early experiments he sought to answer the question: does growth of a nerve fiber require the participation of the cells that will ultimately form its surrounding sheath? Harrison's method was to remove the source of spindle-shaped sheath cells in an embryonic stage before any nerve fibers were present. This he accomplished by cutting a thin strip off the dorsal surface of frog embryos, removing the neural crests. Amphibian embryos survived this operation and developed fairly normally. However, they were without sensory nerves and ganglia, since the neural crests are also the source of these cells. Motor nerves did develop in such animals. Instead of being cellular in structure as they would normally have been, however, the nerves consisted of naked fibers. These first experiments involved only the spinal motor nerves. By 1906 Harrison73 had obtained comparable results in two other amphibian species, and had been able to show that cranial nerves could also develop in the absence of sheath cells. Thus Harrison demonstrated that sheath cells were not essential for the formation of peripheral motor nerve fibers, but he could not rule out the possibility that sheath cells, as well as ganglion cells, might normally form some of the fibers. To determine whether or not this was the case, Harrison attempted to remove the source of motor nuclei by cutting away the ventral half of the medullary cord while leaving the dorsal half and neural crests intact. This, as may be imagined, was an extremely difficult operation. In those cases in which it was successful he found either a marked reduction or more usually a total absence of motor fibers in the abdominal wall ( a convenient area for study because motor and sensory fibers are distributed differ72. "Neue Versuche und Beobachtungen fiber die Entwicklung der peripheren Nerven der Wirbeltiere," S.-B. Niederrh. Ges. Natur. Heilk. (Bonn), B55-62 (1904). 73. "Further Experiments on the Development of Peripheral Nerves," Amer. J. Anat., 5 (1906), 121-131.

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ently). These results suggested that sheath cells were themselves unable to form nerve fibers. It was impossible to perform the comparable experiment with sensory nerves, since the source of sheath cells and ganglion cells is identical. However, there was observational evidence that in several different systems sheath cells were not always present on young sensory nerves. From his experiments Harrison concluded that sheath cells found on developing nerve fibers had nothing to do with their genesis. This experimental evidence suggested strongly that the multicellular theory of nerve fiber development must be basically incorrect. 2. Does the Growth of a Nerve Fiber Occur Only in Areas That Were in Some Way Prepared for It? Two different sorts of experiments were devised to answer the question: does the growth of a nerve fiber occur only in areas that were in some way prepared for it. These involved observation of nerve fiber development after transplantation of nervous tissue to abnormal sites either within the body or outside it (tissue culture). Perhaps the most brilliant experiment of the first type was that reported by Hermann Braus74 in 1905. Braus transplanted limbs of very young tadpoles to various parts of the bodies of other tadpoles, and examined nerves in the transplanted limb. He found that no matter where the limb was implanted, its peripheral nerves would be distributed in the normal manner for that appendage had it been left in its original position. The question Braus asked himself was how this pattern of nerve distribution had occurred. Had the beginnings of the nerves (in the form of protoplasmic bridges) been transplanted with the limb, or had nerves grown in from the host and been guided by the organization of muscle and other structures in the transplanted limb? To answer this question, Braus devised a method of removing the entire central nervous system from a young tadpole, so that the animal developed without peripheral nerves. He found that when a limb from such an animal was transplanted to a normal animal, no nerves developed within the appendage. From this result Braus concluded that there must be a peripheral contribution to the formation of nerve fibers. He reasoned that when he removed the central nervous system from the very young larva he destroyed the peripheral nerve-building factors, 74. "Experimentelle Beitrage zur Frage nach der Entwickelung ipherer Nerven," Anat. Anz., 26 (1905), 433-479.

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Concepts of Nerve Fiber Development much in the same way that the distal portion of a nerve fiber undergoes degeneration when it is severed from the cell body. Therefore, according to Braus, no nerve fibers could be formed in the limb at a later time. This experiment provided compelling evidence in favor of the protoplasmic bridge theory of Hensen or of Held's modified version, and was interpreted in this way by Braus. However, supporters of these theories did not generally use the results of Braus's experiment as part of their arguments. Presumably this lapse reflects the general lack of understanding of the new experimental approach. Braus's work did, of course, attract the attention of Harrison. The latter repeated the same experiments on two different amphibian species.75 The results obtained were completely different. Harrison found that the transplanted "nerve-free" limb did in fact become innervated, although the completeness of innervation varied considerably. The source of these normal nerves could only have been the host's nerve centers. The patterning of their distribution must have depended upon structures within the transplant, since the nerves of the host would not normally have been involved in limb innervation. The contradictory results obtained by Braus and Harrison could perhaps be accounted for by the fact that they worked with different species. There may also have been some variation in operative technique. Whatever the reason, the actual outcome of the experiments did not give strong support to either side. Although Warren Lewis's work was not primarily directed toward studying nerve fiber development, he did a number of experiments that provided evidence favoring the outgrowth theory.70 The presence of Harrison in the same department at Johns Hopkins must certainly have been a factor in focusing Lewis's attention on the paths taken by nerve fibers after transplantation of the optic vesicle or olfactory pit. In one of Lewis's experiments the optic vesicle and a portion of the adjoining neural tube of an Amblystoma larva were transplanted midway between the optic vesicle and medulla of a slightly older animal. Lewis found that nerve fibers extended 75. Ross G. Harrison, "Experiments in Transplanting Limbs and Their Bearing upon the Problem of the Development of Nerves," J. exp. Zool., 4 (1907), 239-281. 76. Warren H. Lewis, "Experimental Evidence in Support of the Outgrowth Theory of the Axis Cylinder," Proceedings, Association of American Anatomists, 1905, Amer. J. Anat., 5 (1905), X-XI; "Experimental Evidence in Support of the Theory of Outgrowth of the Axis Cylinder," Amer. J. Anat., 6 (1906), 461-471.

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out from the piece of donor brain and ran in various directions in the mesenchyme of the host without reaching any end-organ. Under these conditions no protoplasmic bridges could have existed connecting the donor nerve cells with the host mesenchyme. Similarly, he could not explain by the protoplasmic bridge theory several other cases in which nerve fibers grew along abnornal paths: the growth of olfactory nerve fibers into mesenchyme filing an area from which part of the forebrain had previously been removed; the growth of optic or olfactory nerves from transplanted optic cups or olfactory pits. Lewis concluded from his experiments that nerves do not grow only in areas that have been prepared for them. They are capable of developing in totally foreign territory. Harrison reported the results of rather similar experiments in 1906.77 He found that when the entire spinal cord of an anuran larva was removed at an early stage no spinal peripheral nerves were present, demonstrating that nerve fiber formation required the presence of neuroblasts. In addition, he observed that the space previously occupied by the spinal cord became ifiled in with mesenchyme. Through this area grew longitudinal bundles of fibers that arose at higher levels. That is, fibers were capable of growing in abnormal paths where it was unlikely that preformed bridges existed. Harrison realized almost immediately that transplant experiments sometimes gave uncertain results because two problems, the source of a nerve fiber and the orientation of its growth, were considered together. If nervous tissue could be successfully grown outside the body, these two factors would be separated and the source of a nerve fiber could be independently demonstrated. Paul Weiss78 has stated that to his knowledge Harrison never conceived issues, rather he settled them. Never perhaps was Harrison's particular genius more clearly demonstrated than in the design of the elegant tissue culture experiment from which he obtained evidence that not only opposed the multicellular and protoplasmic bridge theories but also suggested how outgrowth might be accomplished.79 As reported in his 1907 and 1910 papers, Harrison's method was to isolate parts of the embryonic central nervous system. Pieces were removed from the neural tubes of anuran embryos 77. Harrison, "Further Experiments on the Development of Peripheral Nerves" (1906). 78. Personal communication. 79. Ross G. Harrison, "Observations on the Living Developing Nerve Fiber," Anat. Rec., 1 (1907) 116-118; "The Outgrowth of the Nerve Fiber as a Mode of Protoplasmic Movement," J. exp. Zool., 9 (1910), 787-846.

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Concepts of Nerve Fiber Development before any formation of nerve fibers had begun and were clotted onto a coverslip with a drop of lymph. The coverslip was then inverted over a well slide, forming a hanging-drop culture that could be observed microscopically using an objective with a long working distance.80 Harrison found that under these conditions cells of individual tissues appeared to differentiate normally, although they did not assume the spatial configuration typical of the normal embryo. In his cultures Harrison observed the presence of numerous nerve fibers. Occasionally these left the explanted tissue and extended into the peripheral area filled with clotted lymph. It was possible to watch the growth of such fibers and to record their history. He described one of his cultures: This same preparation showed a number of . . . fibers of interest. Among them was one which arose from a single isolated cell, and which was visible throughout its entire length. When first observed this fiber had a total length of 453 ,. At a distance of 303 ,u from the cell it bifurcated, the longer branch being 150 u and the shorter, which afterward grew to be the longer, 107u. At this time, the ends were not very active and that of each branch was almost globular, but with one blunt pseudopodium. The cell itself was unipolar. Examined at the expiration of four hours and three quarters, the change in the fiber was found to be very great. The cell itself was unchanged but the fiber then had a total length of 631 i, and one of the original branches had again bifurcated. All three of the terminal enlargements were exceedingly active, and all were provided with a number of fine filaments. The increase in length from the cell to the tip of the longest branch was 221 /A,which is at the rate of .77+ ,Aper minute, or 46.5 ,u per hour. Comparison of the two stages shows that the greater part of this was due to terminal growth, but the distance between the cell body and the first bifurcation increased 21 ,u, and the curvature of this part of the fiber was partially straightened out.8' Under circumstances where it was possible to measure fiber growth from a fixed point in the culture, it became apparent that a fiber elongated at its tip. That is, during growth the 80. As Jane M. Oppenheimer has pointed out in "Ross Harrison's Contributions to Experimental Embryology," Bull Hist. Med., 40 (1966), 525-543, Harrison was not the first investigator to attempt the method of tissue culture. However, primarily because of his use of lymph rather than saline as a culture medium, he was the first to succeed. 81. Harrison, "The Outgrowth of the Nerve Fiber" (1910), 815.

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position of the cell body remained fixed while that of the fiber tip changed. From his studies Harrison came to the conclusion that . . . the extension of the fiber is due to the activity of the enlargement at its end. The character of the movement that takes place at the end of the fiber is difficult to describe. The filaments in which the fiber ends are extremely minute and colorless, showing against their colorless surrounding only by difference in refraction. The eye perceives, therefore, only with difficulty an actual movement.82 Harrison believed the structure he described at the extreme tip of a growing fiber to be a growth cone. The ameboidal movement he was actually able to see at the growing end of a fiber confirmed what Cajal and Lenhossek had postulated on the basis of Golgi studies. Harrison failed, however, to make clear the exact way in which the nerve fiber developed. The following two statements, made twenty-six years apart, summarize his view. . . . the nerve fiber develops by the outflowing of protoplasm from the central cells. This protoplasm retains its amoeboid activity at its distal end, the result being that it is drawn out into a long thread which becomes the axis cylinder.83 The substance of the axone originates in the neuroblast and is spun out by means of the amoeboid activity of the end.84 At first reading, both seem to suggest that nerve fiber development occurs by the rearrangement of the parts of the neuroblast without the addition of new material preferentially to any part of the growing fiber. Let us, however, try to follow closely the events that Harrison actually described. If one assumes that during fiber development either no new material is added or it is added uniformly, then, after a fiber has bifurcated, the branch-point should be continuously pulled away from the cell body by the ameboid tip. Harrison observed, however, that this was not the case; that is, branch-points remained fixed in position during subsequent lengthening of a fiber. Under these same conditions, if the branch-point is some82. Ibid., p. 819. 83. Harrison, "Observations on the Living Developing Nerve Fiber" (1907), 118. 84. Ross G. Harrison, "On the Origin and Development of the Nervous System Studied by the Methods of Experimental Embryology," (1933) reprinted in Organization and Development of the Embryo, S. Wilens, ed. (New Haven: Yale University Press, 1969), p. 124.

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Concepts of Nerve Fiber Development how anchored to the substratum, then the fiber should become increasingly narrower distal to this point as it is pulled out. But Harrison also noted that this did not occur. Therefore he must doubtless have come to the conclusion that new material was synthesized and added preferentially to the tip of the fiber. Where this material was taken into the cell and synthesized into nerve fiber components Harrison never stated explicitly. However, if questioned, he would probably have suggested that these events occurred right at the fiber tip. Harrison's belief that the tip had ameboid qualities would be in accordance with this view, for it was recognized that intake of fluid occurred at the advancing edge of the ameba. Harrison did not include in his theory the concept of axoplasmic flow, transport of materials from the cell body where they are synthesized to distal regions of the axon where they are utilized. This is not surprising, for although Alfred Goldscheider85 had postulated the existence of axoplasmic flow as early as 1894, his hypothesis was not confirmed experimentally until the early 1940s.86 In Harrison's tissue culture experiment all structures from the periphery that might be thought to transform themselves into nerve fibers were eliminated. There could be no question of the conversion of a multicellular chain into the nerve fiber, for there simply were no such structures in the culture. From microscopic observation of the living, unstained cultures it was evident that the growing fiber was a single, anucleate protoplasmic strand. The only cell type necessary for its formation was the neuroblast. Similarly, the experiment eliminated the possibility that nerve growth required the presence of preformed protoplasmic bridges. Since the solid parts of the culture were only fibrin, it would be impossible to say that growth occurred either by transformation of pre-existing protoplasm or by extension of fibrillar bundles within such a material. Between 1907 and 1910 Harrison was challenged on this conclusion by several proponents of theories requiring the presence of pre-existing structures for nerve growth, particularly Held.87 The essence of Held's argument was that although a nerve fiber could form in vitro without pre-existing structures, its normal 85. "Zur allgemeinen Pathologie des Nervensystems. I. Ueber die Lehre von den trophischen Centren," Berlin. Klin. Wochenschr., 31 (1894), 421-425. 86. Paul Weiss, "Damming of Axoplasm in Constricted Nerve: A Sign of Perpetual Growth in Nerve Fibers," Anat. Rec., 88 (suppl.) (1944), 464; "Evidence of Perpetual Proximo-distal Growth of Nerve Fibers," Biol. Bull., 87 (1944), 160. 87. Held, Die Entwicklung des Nervengewebes.

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development in vivo in which the fiber grew to make some functional connection could still require their presence. Rebuttal of this argument was extremely difficult. Harrison was willing to agree that some network might guide the developing fiber, but he was convinced that if this were the case the fiber would grow along, not within, such a structure. The other major disagreement between Held and Harrison concerned the nature of the growing process. Held, as we saw previously, believed that the growing portion of the nerve consisted of a fibrillar bundle. Harrison, on the other hand, maintained that there were two events in nerve fiber formation. One was the formation of a primitive nerve fiber by the extension of neuroblast protoplasm into a thin strand. The second was the differentiation of fibrils within this strand. In 1911 Montrose Burrows88 made the first successful fixed preparations of nerve fibers grown in hanging-drop cultures. Both Held's molybdenum-haematoxylin and Cajal's reduced silver methods revealed the presence of neurofibrils in the cultured fibers. Since neurofibrils were considered morphological markers for a nerve fiber, this finding dispelled the rather common argument that nerve fibers were not the structure being observed in culture. Burrows described the tips of fibers in his stained preparations: The end bulbs appear as faintly stained enlargements at the end of axis cylinders. The end bulbs and their pseudopodia stain irregularly, showing one or more dark staining bands which pass from the nerve fibre to the different pseudopodia. This dark-staining material may often be broken and appear as dark-staining globules, lying in the main mass of the bulb.89 This description closely resembles that of in vivo growth cones stained in a similar way. Further studies of hanging-drop cultures by W. H. Lewis and M. R. Lewis90 in 1912 and Giuseppe Levi9l in 1916 served to confirm Harrison's original contention that growth of a nerve fiber depended solely upon the neuroblast. Apparently the proponents of the multicellular theory were swayed in their opinions neither by the results of the experi88. "The Growth of Tissues of the Chick Embryo Outside the Animal Body, with Special Reference to the Nervous System," J. exp. Zool., 10 (1911), 63-83. 89. Ibid., p. 74. 90. "The Cultivation of Sympathetic Nerves from the Intestine of Chick Embryos in Saline Solutions," Anat. Rec., 6 (1912), 7-31. 91. "Sull'origine delle reti nervose nelle colture di tessuti," Rend. R. Acad. Lincei, Cl. Sci. Fis. Mat. Nat., 25 (1916), 663-668.

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Concepts of Nerve Fiber Development mental approaches devised by Harrison and discussed previously, nor by the observational data available. The latter included the beautiful descriptive work of Ramon y Cajal (organized as an argument against the multicellular theory in a review article published in 1905),92 Held (summarized in Die Entwicklung des Nervengewebes bei den Wirbeltieren, 1909) and Henry V. Neal (reported in an article on the development of eye muscle nerves in Squalus, 1914).93 The precise correlation that George E. Coghil194 was able to find between the stage of development of the nervous system and motor responses in Amblystoma larvae implied a timing in development and beginning of function of nerve fibers that was explicable in terms of the outgrowth theory. It did not in itself, however, rule out the other theories of nerve development. In 1914 Alexander Goette95 published a study on the development of cranial nerves in fish and amphibia. He claimed that nerve fibers were formed in the homogeneous syncytium resulting from the fusion of Bildungszellen. They developed in a centripetal direction, finally joining with ganglion cells of the brain. The appearance of papers like that of Goette forced proponents of the outgrowth theory, notably Cajal and Harrison, to continue fighting in its favor. In 1924 Ross Harrison96 published a long paper in which he reported further experimental evidence against the multicellular theory. By that time he had added further cases to the experiment in which the ventral half of the spinal cord was removed to determine whether or not sheath cells could themselves form nerve fibers. His conclusion remained unchanged; ventral horn cells were the necessary factor for the development of peripheral motor fibers. Harrison had also devised a second related experiment to which skeptics could no longer object that the operation prevented the sheath cells from taking up suitable positions for creating motor fibers. His method was to remove the spinal cord 92. Ram6n y Cajal, "Genesis de las fibras nerviosas" (1905). 93. Henry V. Neal, The Morphology of the Eye Muscle Nerves," J. Morph., 25 (1914), 1-187. 94. "Correlated Anatomical and Physiological Studies of the Growth of the Nervous System of Amphibia. I. The Afferent System of the Trunk of Amblystoma," J. comp. Neurol., 24 (1914), 161-233; "Correlated Anatomical and Physiological Studies of the Growth of the Nervous System in Amphibia. III. The Floor Plate of Amblystoma," J. comp. Neurol., 37 (1924), 37-69. 95. "Die Entwicklung der Kopfnerven bei Fischen und Amphibien," Arch. mikr. Anat., 85 (1914), 1-165. 96. "Neuroblast Versus Sheath Cell in the Development of Peripheral Nerves," J. comp. Neurol., 37 (1924), 123-205.

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after the spinal ganglia had begun their development. At that time motor nerves had started to form, and sheath cells were present on the nerve trunnks. However, after the operation Harrison could find no motor nerves. That is, sheath cells were unable even to continue the formation of axons. The only conclusion that can be drawn from this and the previous experiment is that sheath cells cannot form motor nerves in the absence of motor ganglion cells. The combination of improved observational techniques and accumulation of experimental data finally completely discredited the multicellular theory. The results of the various transplantation experiments discussed previously seem to provide almost overwhelming evidence against the protoplasmic bridge theory. It did still have a few proponents, however. One of the last papers in which it received support appeared in 1922. Raymond A. Dart and John L. Shellshear97 claimed that in Squalus the inner wall of the somite gave rise to motor neuroblasts. These cells were believed to migrate into the neural tube while maintaining contact with the myotome. The nucleus of the cell ultimately resided in the neural tube while the cell's protoplasm, strung out from spinal cord to periphery, formed a bridge in which the axons developed. These bizarre findings were contradicted by the earlier observations of Harrison98 and Neal.99 Presumably the authors mistook migrating connective tissue cells of the dissociating sclerotome for neuroblasts.100Certainly nothing in the poorly documented paper would lead one to suspect otherwise. CONCLUSION It was thus the combination of observational and experimental approaches that ultimately led to confirmation of the outgrowth theory. The observational method was essential for defining various possible methods of nerve fiber development. The multicellular, protoplasmic bridge and outgrowth theories were each postulated to explain purely observational evidence. However, the lack of truly suitable equipment and techniques to study the developing nervous system made it impossible to agree on a single theory on this basis alone. The experimental method 97. "The Origin of the Motor Neuroblasts of the Anterior Cornu of the Neural Tube," J. Anat. (Lond.), 56 (1922), 77-95. 98. "Ueber die Histogenese des peripheren Nervensystems bei Salmo salar," Arch. mikr. Anat., 57 (1901), 354-444. 99. "Nerve and Plasmodesma," J. comp Neurol., 33 (1921), 65-75. 100. See Harrison, "Neuroblast Versus Sheath Cell" (1924), 128.

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Concepts of Nerve Fiber Development provided a means of choosing between these theories. Without the preceding observations that had led to the formulation of various hypotheses, however, the experimental approach might not have been so successful, for the power of this method is more of selection than of generation. Therefore it is impossible to weigh separately the contributions of the observational and experimental approaches to the question of nerve fiber development. Both were necessary for the ultimate acceptance of the outgrowth theory. Acknowledgments I would like to thank Sanford L. Palay and Everett Mendelsohn for their valuable comments on the manuscript, and Hermann Lisco for his help with the German translations. This study was supported by U.S. Public Health Service Training Grants GM00406 and NS-05591.

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New Formation of Organs in Plants The Foundation of Plant Morphogenesis KRAFT E. VON MALTZAHN Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada

*The author gratefully acknowledges receipt of a Killam fellowship from Dalhousie University. He wishes to thank Professor Erwin Bunning for the hospitality of his laboratory at Tubingen University. It was here that Vochting was o. Professor from 1887 until his death in 1918 and Klebs was recognized as Privatdozent in 1883.

We are often not aware of the unusually rich conceptual understanding of biological processes which evolved in the second part of the nineteenth century in Germany. This is illustrated by the early investigations into the question of the site of new formation of organs in plants. These investigations represent the foundation of modern plant morphogenesis. Questions concerning the direction of movement of sap in plants and the nature of their conducting elements are very old. Possible relationships between sap movement and new formation of organs in plants were investigated carefully by Johannes von Hanstein.1 Are there two different kinds of sap of which only one is capable of bringing about new formation of organs? Is the necessary plastic material already present at the site of the new formation or is it formed there from the sap? Hanstein applies the method of stem-ringing in order to answer these questions; i.e., at some specific site he removes the bark, including the cambium, around the axis, leaving only wood as the continuous longitudinal tissue at this site. Some time after this operation he observes the distribution of newly formed roots. If the site of formation of the plastic sap responsible for the new formation of organs coincides with the site of organ formation, ringing the stem should not affect the new formation. 1. J. von Hanstein, "Versuche iiber die Leitung des Saftes durch die Rinde," Jahrb. f. wissenschaftl. Botanik, 2 (1860), 392. Journal of the History of Biology, vol. 4, no. 2 (Fall 1971), pp. 307-317.

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Hanstein observes, however, that complete ringing drastically affects the position of sites of new formation. Roots are formed from tissues outside the wood just above the ring. It thus appears that the site of formation of the plastic sap and the site of its use in the new formation of organs do not coincide. Rather, the sap responsible for the new formation of organs is conducted in a downward direction through the bark only and must accumulate above the ring causing here the formation of adventitious roots. In other experiments Hanstein applies only partial ringing, by leaving a small bridge between the bark above and below the ring. He observes that the small bridge is sufficient to allow transport of the plastic sap through the site of the partial ring in a downward direction. Since in this case the plastic sap does not accumulate above the site of partial ringing, roots are not formed here but only at the base of the stem where they would be formed anyway in non-ringed plants. Additional experiments led Hanstein to conclude that although roots are necessary for root sap to move in an upward direction to the leaves, the materials assimilated in the leaves can only move downward through the bark. It is this plastic sap which is responsible for new formation wherever it is permitted to accumulate. Which factors are responsible generally for the determination of sites of formation of plant organs? This question concerned Hermann V6chting2 who published in 1878 an important book Uber Organbildung im Pflanzenreich (About organ formation in plants). Here he describes extensive experiments designed to answer questions about the site of reactivation of resting organ primordia and about the site of new formation of roots and buds through regeneration within isolated segments of stem or root. In many of his experiments he uses pieces of willow stem cut to specific lengths. He removes the leaves from them and hangs them in various positions, right side up, upside down, or horizontally in closed moist glass cylinders. In other experiments various parts of isolated pieces are treated with water, moist soil, presence of light of different intensities or absence of light, etc. Vochting's theoretical considerations on which his experimental designs are based must be described briefly. He distinguishes between internal forces in general and those internal forces which specifically condition form-development (morphological forces). He distinguishes these from the external forces. According to Vochting, phenomena of inheritance are based on 2. H. Vochting, tYber Organbildung im Pflanzenreich (Bonn: Max Cohen & Sohn, 1878) 258 pp.

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New Formation of Organs in Plants the molecular architecture of the cell. Internal forces are considered to be decisive in the determination of specific characteristics of growth while external factors influence growth only indirectly. His interest lies particularly in the relative significance of these forces for the determination of sites of formative events. In stem pieces hung vertically with the apical end pointing up, the apical end exhibits primarily reactivation of lateral buds. Reactivation of existing but resting adventitious roots and new formation of roots, partly through callus formation, take place predominantly toward the basal portion of the isolated stem piece. The contrast between tip and base in the type of organ formed is expressed most strongly in stem pieces obtained from young shoots and in those obtained during the fall.3 He suggests that in these cases the amounts of soluble reserve substances are too small and do not allow production of large numbers of organs. Formation of new organs must therefore remain largely restricted to the ends of the stem segment. Similar results are obtained with very small stem segments which consist only of part of one internode. When Vbchting hangs stem segments of Salix in a vertical position but with the apical end down and the basal end up, the apical end still shows lateral bud reactivation and the basal end reactivation and new formation of adventitious roots. Vochting concludes from these experimental observations that the external force of gravity cannot be the decisive force in the determination of the site of formation of new organs within the whole plant or within its parts. If gravity were responsible, stem pieces hung upside down should form roots and reactivate buds at the ends of the piece of branch opposite to those observed by Vbchting. The same site may thus become the tip of one isolated stem segment or the base of another stem segment depending upon its former position within the whole intact plant. As soon as a stem segment of a plant is isolated, specific forces become active which bring about opposite formative processes at the two ends of the isolated segment. Vochting carried out similar experiments with isolated root segments, mainly of poplar. At the cut end near the former basal pole, adventitious shoots are formed. At the cut end near the former tip of the root, mainly callus is formed and few or no roots. Vochting thus finds polar differences within the root similar to those within the stem in the distribution of type of 3. H. Vochting, "uber Regeneration und Polaritat bei hoheren. Pflanzen," Bot. Zeitung, 64 (1906), 101.

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new formation. Root and shoot differ in behavior in that within the shoot buds are formed near the apex and roots at or near the base; in the root, buds are formed at the base and roots near the tip end of the root segment. Stem and root each forms therefore at its respective tip the morphological structure corresponding to itself and at its base the morphological opposite. Vochting finds also that a morphological unit produces more readily the morphological opposite than it does the equal. A stem internode thus produces more readily roots and a piece of root more readily shoot buds In addition to stem and root Vochting examines sites of formative processes in isolated leaves, particularly of Begonia. Isolated segments of petioles first form roots and later buds, both at the basal end of the petiolar segment. When the petiole is isolated from the stem but with a piece of leaf lamina attached to it, roots are formed initially at the basal end of the petiole. Later, this is followed by new formation of shoot buds on the upper, or adaxial, side where the lamina fuses with the petiole, and these buds soon form adventitious roots at their base. If the lamina is isolated without the petiole and the main nerve is cut at right angles to the longitudinal axis of the leaf, buds are formed near the wound at the basal end of the nerve. This is followed by root formation at the same site. Vochting finds that the orientation of the lamina pieces has little influence upon either site or type of new formation. Even though, in leaves, root formation often precedes shoot bud formation, both organs or organ systems are often formed at the same site within the organ or organ part following its isolation. The behavior of the leaf is in contrast to the behavior of both stem and root. Vochting discusses these behavioral differences in terms of symmetry relations within these organs and in terms of the role of determinate versus indeterminate growth characteristics of these organ systems. Differences in growth characteristics seem to him to be more significant in determining differences in the relative site and type of formative processes between different organs. Of the environmental factors which could be important, Vdchting examines particularly the role of water, oxygen, light, and gravity. When he puts stem segments of Salix in different orientations to the axis of the gravitational field he observes that the smaller the angle of the longitudinal axis of the organ to that of the gravitational field the more the buds grow all around the tip of the segment. With a greater angle the buds still grow around the tip but also starting from it away from it on the upper side of the segment. Horizontal orientation of the

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New Formation of Organs in Plants segment still results in new formation around the tip and away from it on the upper side of the segment only. The same is true for changes in the site of formation of new roots within the stem segment as related to segment orientation. When the horizontal orientation is approached, roots are formed all around the base of the segment and away from the base on the underside. Since the type and the amount of new formation of organs is found by V6chting to be determined primarily by the site which the regenerating segment held within the complete organism, and only to a limited extent secondarily through external forces, he concludes that the developmental form of a cell is primarily determined by its site within the whole organism. He considers the differences in polar behavior between tip and base in higher plants to be essentially unalterable. Polarity is therefore a general structural characteristic of living tissues and of its constituent cells and is of an inheritable nature. Polarity in itself has nothing to do with regenerative new formation but influences the site of new formation. Polarity is effective not only in isolated plant parts but within the intact plant as a whole.3 Vochting's conclusionsw were discussed and strongly criticized by Julius Sachs in Stoff und Form der Pflanzenorgane (Substance and form of plant organs). Particularly in his first article under this title, Sachs5 attempts to show that form, with which morphology is concerned, is only the external expression of the presence of substances and of forces which move substances. Differences in external form are the expression of differences in substances and are therefore derived causally by differences in substances. Hence Sachs postulates that there must be as many specific organ-forming substances as there are different organs. Small quantities of these substances must be mixed with the large amounts of unspecific substances, and in combination with them are responsible for specific organ formation. He postulates that external factors such as gravity and light influence differentially the distribution of these specific substances and thereby determine the type and site of organ formed. Thus root-forming substances would move parallel to the direction of light and away from the light, and shoot-forming substances would also move parallel to the light but toward it. Distribution of regenerative new formation of roots and shoots is therefore determined by the distribution of substances causing root and 4. H. Vochting, tJber Organbildung im Pflanzenreich II., (Bonn: Emil Strauss, 1884) 200 pp. 5. J. Sachs, "Stoff und Form der Pflanzenorgane I.," Arb. d. bot. Inst. in Wiirzburg, 2 (1880), 452; andVorlesungen iuber Pftanzenphysiologie (Leipzig. Wilhelm Engelmann, 1887), 884 pp.

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shoot formation, and the distribution of these substances within the plant is determined by external conditions. Sachs considers Vbchting's views as taking refuge in mysterious morphological factors which he must reject in the causal explanation of regenerative and other processes. Sachs postulates instead that the site of production of specific organ-forming substances coincides with the main sites of assimilation, i.e., that production takes place within leaves. From here root-forming substances are transported toward the root tip and shoot-forming substances toward the shoot tip. The direction of flow of these substances is due to gravity in that the root-forming substances are transported parallel to the axis of the gravitational field and toward its center, while the shoot-forming substances move away from the center of gravity. When a piece of stem is isolated, as in Vochting's experiments, accumulation of specific organ-forming substances takes place at the cut surface. Since root-forming substances are transported basipetally, they accumulate at the base of the segment and cause here new formation of roots. In segments kept right side up shoot-forming substances are, according to Sachs, transported acropetally away from the center of gravity and form shoots near the tip of the segment. Sachs concludes that Vbchting did not consider sufficiently the influence of gravity upon the intact plant before isolation of the segment. As long as the intact plant had been kept right side up, the longlasting influence of gravity on the distribution of organ-forming substances prior to segment isolation could not be readily overcome even when the segment was turned upside down after isolation. Similarly, Sachs suggests that Vochting did not consider sufficiently differences in regenerative behavior between segments hung in various orientations to the axis of the field of gravity. He concludes that the regenerative behavior of isolated parts of plants is not due to an inherent force determined by the polar differences between tip and base but is due solely to the influence of gravity upon the distribution of specific organforming substances. In 1880, in response to Sachs' views, V6chtingB described experiments with branches from weeping willows which hang downward while part of the intact plant and so are exposed to gravity in an inverted position for long periods prior to segment isolation. For Sachs's objections to Vochting's views to be correct, Vochting should obtain in isolated segments which are hung 6. H. Vochting, "tber Spitze und Basis an den Pflanzenorganen," Zeitung, 38 (1880), 609.

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with their morphological tip down and base up root formation from the morphological tip and bud formation from the base. Vochting, however, still obtains results expected on the basis of his interpretation, i.e., bud formation at the morphological tip and formation of roots at the base. On the basis of these and other considerations Sachs7 modified his interpretation. In addition to external factors such as gravity and light he considers also the internal disposition ("innere Disposition") within the plant. According to this interpretation, both external factors and internal disposition determine directly but differentially the direction of flow of specific organ-forming substances. Gravity, for example, is a force which drives certain specific organ-forming substances in an upward direction and others in a downward direction. When the plant is in its normal position, effects of the internal disposition and of the gravitational influence coincide. When the plant is upside down, the effects of internal disposition and of gravity are opposite to each other. Under these conditions, Sachs postulates, it depends upon the reactivity of the plant whether and to what extent gravity may overcome the internal disposition. While most of these results were obtained by Vochting before the end of the last century, at the beginning of the present century George Klebs8 published an important book on Willkurliche Entwicklungsanderunggen bei Pflanzen (Artificially induced developmental changes in plants). In 1889 Klebs had begun investigating the factors responsible for the initiation of reproduction in lower and higher plants. He states that all characteristics to be realized within the life of the organism must potentially be present within a meristematic cell ("Zelle des Vegetationspunktes"). These potentialities are determined through the species-specific chemical and physical composition of the system. This system of mutually interrelated chemical and physical conditions which remain constant he calls specific structure ("spezifische Strucktur"). He separates from it the internal conditions which are variable and are connected with the external conditions. According to Klebs, we therefore have something which is constant, namely, the specific structure, and two variables, the internal and the external conditions. The specific structure determines through the arrangement of the 7. J. Sachs, "Stoff und Form der Pflanzenorgane II.," Arb. d. bot. Inst. in Wiirzburg, 2 (1882), 689. 8. G. Klebs, Willkurliche Entwicklungsdnderungen bei Pflanzen (Jena: Gustav Fischer, 1903), 166 pp.

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component parts of the system the kind of possible changes. The internal conditions are changed through the external conditions and affect the constant structure. Klebs attempts to show that certain developmental processes are causally related to known external conditions. His goal is to analyze each form development through knowledge of its conditions. He contrasts growth and reproduction and wants to relate conditions which favor either one or the other of these important developmental processes. He finds generally that all favorable nutritive conditions favor growth and that unfavorable nutritive conditions favor onset of reproduction. The chapter of his book devoted to regeneration tries to show that it is the presence or absence of a complex of conditions which determines whether and where a specific formative event takes place. Thus, reactivation of existing organ primordia, as well as their new formation, depends upon a complex of internal conditions which, when all are present, initiate these specific formative processes. This requires, of course, that the specific structure of the cell contain the necessary potentialities. The internal conditions which affect the specific structure in turn depend on external conditions. According to Klebs, we must try to find these external conditions and we will then be able to bring about specific developmental processes at will. On the basis of these considerations Klebs repeated and modified some of Vbchting's experiments. In particular he applied water locally to various sites of the plant with no injury to the plant. He reached the conclusion that sufficient soaking of the bark through to the cambium makes possible root-formation anywhere. The site of a particular formative process is determined, therefore, by the presence of a complex of conditions. In the present case water represents the factor which is limiting to root formation. Klebs concludes that in the system under consideration polarity does not have an influence on the distribution of sites of new formation of organs. The site is determined rather by the presence of the complex of conditions, with water in the present case as the limiting factor. If water becomes available, regenerative processes can take place equally well everywhere. Even though Klebs denies that polarity plays any role in the distribution of formative processes in the present system, he admits that polarity may play a role in other cases. According to Klebs, polarity cannot be considered to be part of the specific structure. Polarity is concerned with special physiological processes which may differ at the apical and the basal pole as a result of anatomical differences. Since all such processes are

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New Formation of Organs in Plants changeable through interaction with the external world, he concludes that polarity must be reversible. In 1902 Karl Goebel9 published articles about "Regeneration im Pflanzenreich" (Regeneration in plants). He defines regeneration as activation of dormant primordia or new formation of primordia. Leaves of Bryophyllum crenatum contain plantlets normally within notches at the margins of leaves. These plantlets can be activated by means of incisions into the larger veins while the leaf remains attached to the plant. Thus severance of conducting channels brings about activation of dormant plantlets. Plantlets along the margin of a leaf can also be activated through removal of buds from the plant other than those along the leaf margin. Thus the presence of terminal meristems within the intact plant apparently prevents activation of meristems within the plantlets of the leaves. In Begonia Rex no adventitious shoots are present on leaves of intact plants. Isolation of leaves initiates new formation of shoots at the base of the leaf. New formation can be induced elsewhere within the leaf through cutting of the larger veins. Through removal of all buds, new formation of shoots is induced at the bases of leaf blades where the larger veins join. This is accomplished without leaf isolation or cutting of veins. Goebel assumes that the presence of certain amounts of substances, called "building materials," brings about reactivation or new formation of organs or organ systems through local reembryonalization of mature cells. These building materials are formed within the leaves. From the leaves they are transported through the axis of the plant to both the shoot tip and the root tip (see also Hanstein above). According to Goebel, the directional transport is due to polarity. The terminal meristems draw continuously upon these substances. Hence these meristems serve as centers of attraction and incorporation of the building materials. As long as the leaf is attached to the intact plant the building materials necessary for regeneration flow from the leaf into the stem. Here, due to the presence of polarity, they are channeled toward the centers of attraction. Vochting attempts to explain differences in sites of regeneration in isolated leaves and in stem segments through differences in growth characteristics of these organs, i.e., determinate growth in the former to indeterminate growth in the latter. Goebel postulates that detachment of leaves removes these from 9. K. Goebel, "Regeneration im Pflanzenreich," Biol. Zentralbl., 22 (1902), 385; 417; 481; "Regeneration in Plant," Bull. Torrey Bot. Club, 30 (1903), 197.

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the centers of attraction, i.e., the meristems in other parts of the plant. The building material produced within the leaf is now available for the reactivation of meristems already present, as in Bryophyllum, or for their new formation as in Begonia Rex. The sites of reactivation and of new formation are therefore determined by the distribution of building material within the plant or within isolated parts of the plant. Distribution of the building material in turn is determined by the distribution and relative strength of centers of attraction, and their integration through polarity resulting in directional flow of this material. In order to learn more about conditions necessary for growth and division of cells, Gottlieb Haberlandt'0 carried out experiments with isolated plant cells. Although he observed enlargment of these cells, he was unable to produce conditions which would permit them to divide. Later," he isolated larger tissue complexes from potato tubers and observed cell divisions in parenchymatous cells as long as these were in contact with parts of vascular bundles, more specifically with sieve tube elements and their companion cells. He concluded that these cells of the phloem tissue give off stimulatory substances which, together with the wound stimulus, bring about division of parenchymatous cells. He reports about experiments designed to clarify the nature of the wound stimulus involved in the initiation of cell divisions.12 His experiments are designed to test his hypothesis of the action of wound hormones in the initiation of cell divisions. Haberlandt understands under this concept substances which are products of decomposition in dying or dead cells which have specific physiological effects in living cells when these substances enter such cells. In order to test this hypothesis he isolates segments from stem tubers of kohlrabi and treats these as follows: (a) the wound surface is washed forcefully with water; (b) the same treatment as in (a) but with additional application of juices from potatoes after washing; (c) same treatment as in (a) but with the additional application of juices from kohlrabi after washing; and (d) the wound surface is not washed. He obtains extensive cell divisions in pieces treated as described under (c) and (d). These divisions take place in parenchymatous cells near the wound surface, and the plane of new-wall formation is predominantly parallel to the wound surface. In 10. G. Haberlandt, "Kulturversuche mit isolierten Pflanzenzellen," Sitzsber. Akad. Wiss., Wien, Math.-Naturwiss. Kl., 3 (1902), 69. 11. G. Haberlandt, "Zur Physiologie der Zellteilung," Sitzsber. Kgl. Preuss. Akad. Wiss., 16 (1913), 318. 12. G. Haberlandt, "Wundhormone als Erreger von Zellteilungen," BeitT. z. allg. Bot., 2 (1921), 1.

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New Formation of Organs in Plants treatments (a) and (b) he obtains some cell enlargement in cells next to the wound with few or no cell divisions; these show more random orientation of planes of new cell walls. These observations do not contradict the concept of wound hormones and indicate that these substances are specific regarding the type of plant which produces them and their effectiveness on living cells. Haberlandt treats leaves of Sempervivum montanum in two different ways: leaves are separated from the rest of the plant either through cutting or through tearing. In the latter treatment, cells are rarely wounded since separation of cells occurs readily along intercellular spaces. In those leaves which are torn off, the plant cells at the open end enlarge but rarely undergo division. Those leaves to which a wound surface is applied through cutting exhibit extensive cell-divisional activity and formation of wound cork. In both treatments leaves are isolated. Isolation can therefore not be the factor sufficient for the initiation of cell divisions in these leaves. Haberlandt concludes that products of decomposition of disintegrating protoplasm are essential as wound hormones in the induction of cell divisions. Renewed divisional activity is an important event in the new formation of organs or organ systems, and the possible role of wound hormones in the determination of onset and site of new formation must be thought of. The building stones toward an understanding of the site of new formation of organs in plants was laid by the turn of the century and Haberlandt's work leads us well into the modern period of studies in plant morphogenesis.

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Sir William Lawrence (1783-1867) A Study of Pre-DarwinianIdeas on Heredity and Variation KENTWOOD D. WELLS Section of Ecology and Systematics Cornell

University

Ithaca, New York

INTRODUCTION Of the many British biologists of the early nineteenth century who have been neglected by historians of science, one of the most interesting is Sir William Lawrence. Despite the fact that Lawrence was evidently the first man to introduce the term "biology"into English usage, a standard reference on the history of biology such as Nordenskiold's detailed treatment makes no mention of him.' In other works, if he is mentioned at all, it is often in a brief paragraph or footnote. There is no full biography of Lawrence, and only a few brief biographical sketches are available. Unfortunately, much of what has been written about him is inaccurate and misleading. In the last ten years there has been a slight revival of interest in Lawrence, begun largely by C. D. Darlington's claim that Lawrence was a full-fledged forerunner of Darwin.2 Darlington's brief treatment has been used as the basis for even briefer discussions by a number of other authors.3 Darlington is not 1. Erik Nordenskiold, The History of Biology (New York: Tudor Publish. ing Co., 1935). On Lawrence's use of the term "biology," see: William Lawrence, Lectures on Physiology, Zoology, and the Natural History of Man (Salem, Mass.: Foote & Brown, 1828), p. 65; June Goodfield-Toulmin, "Blasphemy and Biology," Rockefeller University Review, 4 (1966), 14; Charles Singer, A History of Biology, rev. ed. (New York: Henry Schuman, 1950), p. 294n. 2. C. D. Darlington, Darwin's Place in History (New York: Macmillan, 1961), pp. 16-24; "The Origin of Darwinism," Scientific American, 200 (May 1959), 60-66. 3. Sir Alister Hardy, The Living Stream (London: Collins, 1966), p. 58; Desmond King-Hele, Erasmus Darwin (New York: Scribner's, 1963), p. 78; Gordon Rattray Taylor, The Science of Life (London: Thames & Hudson, 1963), p. 143. Journal of the History of Biology, vol. 4, no. 2 (Fall 1971), pp. 319-361.

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the first to suggest that Lawrence anticipated Darwinian evolution. As early as the 1890's, during a period of great interest in forerunners of Darwin, Lawrence was cited as having anticipated certain aspects of Darwin's theory, and several writers since then have repeated the suggestion.4 In addition, a number of recent authors have focused their attention on other aspects of Lawrence's work, especially his physiological theories of life and the function of the brain.5 This paper will deal principally with Lawrence's views on heredity and race formation in man and with his position in the development of the theory of evolution. These are the aspects of his work which have been most often confused. William Lawrence was born in 1783 and died in 1867. He advanced rapidly in his medical education and at sixteen was made an apprentice to the well-known surgeon, John Abernethy, at St. Bartholomew's Hospital. He was appointed a demonstrator in anatomy in 1801. In 1804 he became a member of the Royal College of Surgeons, in 1813 a Fellow of the Royal Society, and in 1814 an assistant surgeon at St. Bartholomew's. Meanwhile he had begun publishing at an early age. While still an apprentice to Abernethy, he was asked to write a series of articles on anatomical and physiological subjects for Abraham Rees's Cyclopedia, and he continued to contribute articles until the work was finished in 1820. He also published translations of Murray's Arteries of the Human Body from the Latin, and Blumenbach's Comparative Anatomy from the German, in 1801 and 1807 respectively. In 1816 he published a series of lectures entitled An Introduction to Comparative Anatomy and Physiology, a book which inaugurated a fierce controversy with 4. Jonathan Hutchinson, "In Memory of William Lawrence," Nature, 56 (1897), 200-201; D. J. Cunningham, "Anthropology in the 18th Century," J. Royal Anthro. Inst., 38 (1908), 30-34; A.C. Haddon, History of Anthropology (London: Watts & Co., 1910), p. 55; Burton Chance, "Sir William Lawrence in Relation to Medical Education," Annals of Medical History, 8 (1926), 273; T. K. Penniman, A Hundred Years of Anthropology (London: Macmillan, 1935), p. 64; Conway Zirkle, "Natural Selection Before the 'Origin of Species'," Proc. Amer. Phil. Soc., 84 (1941), 109-110; E. W. Count, "The Evolution of the Race Idea in Modem Western Culture During the Period of the Pre-Darwinian Nineteenth Century," Trans. N. Y. Acad. Sci., ser. II, vol. 7 (1945), 154-159; M. J. Sirks and Conway Zirkle, The Evolution of Biology (New York: Ronald, 1964), p. 315. and Biology"; June Goodfield"Blasphemy 5. Goodfield-Toulmin, Toulmin, "Some Aspects of English Physiology; 1780-1840," Journal of the History of Biology, 2 (1969), 283-320; Thomas S. Hall, Ideas of Life and Matter (Chicago: University of Chicago Press, 1969), II, 228-230; Philip C. Ritterbush, Overtures to Biology (New Haven: Yale University Press, 1964), pp. 189-191; Owsei Temkin, "Basic Science, Medicine, and the Romantic Era," Bull. Hist. Med., 37 (1963), 97-129.

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Sir William Lawrence Abernethy and others on the nature of life. In 1819, he published his Lectures on Physiology, Zoology, and the Natural History of Man, the book which is the subject of this paper.6 Lawrence's two sets of published lectures, particularly the second volume (1819), caused a great furor because of his views on the nature of life and on the function of the brain, which brought charges of materialism upon him. The details of this controversy have been fully discussed in papers by June GoodfieldToulmin and Owsei Temkin, and they need not be repeated here.7 Suffice it to say that Lawrence withdrew his lectures from circulation to save his medical career. Although they were reprinted many times by various publishers after Lawrence was denied copyright, he never wrote anything more on these subjects, but confined his writings to purely medical treatises. The decision to suppress his lectures was evidently a wise one, for Lawrence went on to a brilliant career as a teacher and surgeon, eventually becoming Sergeant-Surgeon to Queen Victoria.8 Lawrence was an impressive lecturer who had a profound effect on his listeners. The style of his writing is unusually clear and precise for his period and conveys an impression of a vast amount of knowledge. We can get some idea of the impact which the young Lawrence had on his audience from Sir James Paget's description of lectures he attended in the mid-1830's. Those of Lawrence, were, I think, the best then given in London: admirable in their well collected knowledge, and even more admirable in their order, their perfect clearness of language, and the quiet attractive manner in which they were delivered . . . He used to come to the Hospital in the omnibus, and, after a few minutes in the Museum, would as the clock struck, enter the theater, then always full. He came with a strange vague outlook as if with uncertain sight; the expression of his eyes was always inferior to that of his other features. These were impressive, beautiful, and grandsignificant of vast mental power well trained and well sustained. He came in quietly, and after sitting for about half a minute, as if gathering his thoughts, began, in a clear, rather high note, speaking quite deliberately in faultless words 6. Benignus Winslow Forbes, Physic and Physicians (London: Longman, Orme, Brown & Co., 1839), IV, 360-378; Norman Moore, "William Lawrence," DNB., XI, 727-728. 7. Goodfield-Toulmin, "Blasphemy and Biology" and "Some Aspects of English Physiology" (n. 5 above); Temkin, "Basic Science" (n. 5 above). 8. Chance, "Sir William Lawrence . . ." (n. 4 above), pp. 270-279; Moore, "William Lawrence" (n. 6 above), p. 728.

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as if telling judiciously that which he was just now thinking. There was no hurry, no delay, no repitition, no revision: every word had been learned by heart, and yet there was not the least sign that one word was being remembered. It was the best method of scientific speaking that I have ever heard." Lawrence's major work, Lectures on Physiology, Zoology, and the Natural History of Man, was divided into five sections. First there was a lengthy reply to charges made by Abernethy against Lawrence in their controversy on life, in which Lawrence made a strong plea for freedom of scientific enquiry. Following this, there was an historical overview of anatomy and physiology which demonstrated Lawrence's wide knowledge of the literature of those fields, especially the works of French and German writers. The next two lectures dealt with the subjects of life and the function of the brain which caused so much controversy. His main points in the lectures were ( 1 ) that there is no noncorporeal principle of life superadded to organic matter, and (2) that thought is as much the function of the brain as digestion is of the stomach.10 The final portion of the book, which dealt with the "Natural History of Man," contained Lawrence's views on heredity and variation. LAWRENCE'SANTHROPOLOGY Lawrence began his discussion of the "Natural History of Man" by posing a number of questions to be examined from a zoological and physiological point of view: Is he a species broadly and clearly distinguished from all others; or is he specifically allied to the orangutang and other monkeys? What are his corporeal, what his mental distinctions . . . How is man affected by the external influences of climate, food, way of life? Are these, or any others, operating on beings originally alike, sufficient to account for all the diversities hitherto observed; or must we suppose that several kinds of men were created originally, each for its own situation? . . . What was the appearance of the first man? Did he go erect, or on all fours?'1 Lawrence immediately rejected any chain of being which made man "only . . . a more perfect kind of monkey," singling out Charles White's Account of the Regular Gradation in Man 9. Stephen Paget, ed., Memoirs and Letters of Sir James Paget (London: Longmans, Green, & Co., 1901), p. 45. 10. Lawrence, Lectures, pp. 1-103. 11. Ibid., pp. 107-108.

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Sir William Lawrence and in Different Animals and Vegetables (London, 1799) for particular criticism.12 He also rejected the "strange notion" of Rousseau and Monboddo that man and the orangutang are of one species. In his criticism of their theories, Lawrence maintained that these authors "were equally unacquainted with the structure and function of men and monkeys . . . and . . . entirely destitute of the principles on which alone a sound judgment can be formed concerning the natural capabilities and destiny of

animals."13 To illustrate the absurdity of these speculations, Lawrence devoted the next seven chapters to a detailed analysis of the features which distinguish man from the lower animals. His careful marshaling of vast amounts of information culled from voluminous reading reminds one of Darwin's Descent of Man, written over fifty years later. But the point of view was quite different. Darwin concerned himself with similarities between man and animals; Lawrence was concerned with differences. Yet while Lawrence emphasized the distinctness of man, it is clear from his discussion that he considered man very much a part of nature, to be studied like any other object of natural history. In his concept of species, Lawrence was no evolutionist, for he held firmly to the fixity of species, as the following passages show. Animals are characterized by fixed and definite external forms, which are transmitted and perpetuated by generation. The offspring of sexual unions is marked with all the bodily characters of the parents . . . Constant and permanent difference, therefore, is the essential notion conveyed by the word species. Nature has provided, by the insurmountable barriers of instinctive aversion, of sterility in the hybrid offspring, and in the allotment of species to different parts of the earth, against any corruption or change of species of wild animals. We must therefore admit, for all the species which we know at present, as sufficiently distinct and constant, a distinct origin and common date.14 While he stated that species have "fixed and definite external forms," Lawrence realized that a great deal of variation occurs 12. Ibid., p. 110. 13. Ibid., pp. 110-111. 14. Ibid., pp. 226-227, 233.

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in both man and animals. Much of his discussion centered around the analogy between the races of man and the varieties found among domesticated animals. Using this analogy, he attempted to show that human races are members of a single species and that the differences between them are no greater than those found among domesticated animals of a single species. Lawrence discussed the effects of food, climate, and manner of life in altering the physical appearance of human races, for these external factors were generally believed to be responsible for such differences as skin color.15 Unlike many of his contemporaries, however, Lawrence explicitly denied the inheritance of acquired characteristics: Certain external circumstances, as food, climate, mode of life, have the power of modifying the animal's organization, so as to make it deviate from that of the parent. But this effect terminates in the individual. In all the changes which are produced in the bodies of animals by the action of external causes, the effect terminates in the individual; the offspring is not in the slightest degree modified by them, but is born with the original properties and constitution of the parents, and a susceptibility only of the same changes when exposed to the same causes.'6 Since external influences played no role in producing varieties in animals and in man, Lawrence believed that these could only be the result of spontaneous variations. He was unsure of the causes of these variations, as unsure as Darwin was forty years later, but he clearly recognized the existence of this phenomenon: These [diversities] can be explained only by two principles . . . namely, the occasional production of an offspring with different characters from those of the parents, as a native or congenital variety; and the propagation of such varieties by generation. It is impossible, in the present state of physiological knowledge, to show how this is effected; to explain why a gray rabbit can sometimes bring forth at one birth, and from one father, yellow, black, white, and spotted young; why a 15. On various environmentalist theories of race formation, see: Herbert H. Odum, "Generalizations on Race in 19th Century Anthropology," Isis, 58 (1967), 5-18; Samuel Stanhope Smith, An Essay on the Causes of the Variety of Complexion and Figure in the Human Species, ed. with an intro. by Winthrop D. Jordan (Cambridge, Mass.: Harvard University Press, 1965); Thomas Bendyshe, ed., The Anthropological Treatises of Johann Friedrich Blumenbach (London: The Anthropological Society, 1865). 16. Lawrence, Lectures, pp. 89, 436.

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Sir William Lawrence white sheep sometimes has a black lamb; or why the same parents at different times have leucaethiopic children, and others with the ordinary formation and characters.17 According to Lawrence, domesticated animals are much more subject to variation than are wild animals. He saw the adaptation of wild animals to "places which are the most friendly to their constitutions" as a factor which limits variation and preserved the species.18 He was not certain why domesticated animals are more variable than their wild cousins, but he suggested this might be the result of artificial protection, abundance of food, and other similar factors. This notion that domesticated animals are more variable was in part due to Lawrence's ignorance of the role of crossing in producing greater variability, as Robert Olby has shown.'9 It was also due to the fact that apparently spontaneous variations are more readily observable in domesticated animals. Lawrence's prime example of this was the ancon sheep. This variety, which arose by chance, was propagated as a breed, as described in the following passage: A breed of sheep was lately produced in America, the origin and establishment of which confirms the positions already brought forwards. An ewe produced a male lamb of singular proportions and appearance. His offspring by other ewes, had, in many instances, the same characters with himself. These were, shortness of the limbs and length of the body; so that the breed was called the otter breed, from being compared to that animal. The forelimbs were also crooked . . . hence the name 'ancon' (from agkon lelbow]) . . . They were propagated in consequence of being less able to jump over fences.20 Lawrence gave several analogous examples of spontaneous variation in man, including the "porcupine men," who suffered from a congenital, hereditary disease which produced horny bristles on the skin. In his discussion of this peculiar family, Lawrence recognized the role of geographical isolation and interbreeding of similar individuals in maintaining new varieties: Let us suppose that the porcupine family had been exiled from human society, and been obliged to take up their abode in 17. 18. 19. 1966), 20.

Ibid., p. 438. Ibid., p. 438. Robert C. Olby, The Origins of Mendelism pp. 96-97. Lawrence, Lectures, pp. 391-392.

(London:

Constable,

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some solitary spot or desert island. By matching with each other, a race would have been produced, more widely different from us in external appearance than the Negro. If they had been discovered at some remote period, our philosophers would have explained to us how the soil, air, or climate, had produced so strange an organization; or would have demonstrated that they must have sprung from an originally different race; for who would acknowledge such bristly beings for brothers?2' The idea that the "porcupine men" might form a new race was not original with Lawrence. Henry Baker, whose account of the "porcupine men" in the Philosophical Transactions of the Royal Society (1755) was Lawrence's source, suggested that this might be possible, and he even speculated that the colors of the human races might be due to such spontaneous variations. Lawrence seems to have been more aware of geographical isolation as an aid to reproductive isolation, however. This was not mentioned in Baker's account, given below: It appears therefore past all doubt that a race of people may be propagated by this man, having such rugged coats or coverings as himself; and, if this should ever happen, and the accidental original be forgotten, 'tis not improbable they might be deemed a different species of mankind: a consideration which would almost lead one to imagine, that if mankind were all produced from one and the same stock, the black skins of the negroes, and many other differences of the like kind, might possibly have been originally owing to some such accidental foreuse.22 Not only did Lawrence recognize the importance of geographical isolation, but he also dealt with the role of artificial selection in maintaining breeds of domesticated animals. Forty years later, Charles Darwin began his examination of the origin of species with just such a discussion. Lawrence first discussed selection in animals, and then applied the process to man: The formation of new varieties, by breeding from individuals in whom the desirable properties exist in the greatest degree, is seen much more distinctly in our domestic animals than in our own species, since the former are entirely in our power. The great object is to preserve the race pure, by select21. Ibid., p. 387. 22. Henry Baker, "A Supplement to the Account of a Distempered Skin, published in the 424th number of the Philosophical Transactions," Phil. Trans. Royal Soc. (London), 49 (1755), 23.

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Sir William Lawrence ing for propagation the animals most conspicuous for the size, color, form, proportion, or any other property we may fix on, and excluding all others. The hereditary transmission of physical and moral qualities, so well understood and familiarly acted on in the domestic animals, is equally true of man. A superior breed of human beings could only be produced by selections and exclusions similar to those so successfully employed in rearing our more valuable animals.23 Lawrence then added a few more comments on eugenics, spiced with some unfortunate political remarks on royalty, which may have contributed to the hostile reception his book received.24 Continuing his discussion of selection in man, Lawrence wrote: Yet, in the human species, where the object is of such consequence, the principle is almost entirely overlooked. Hence all the native deformities of mind and body, which spring up so plentifully in our artificial mode of life, are handed down to posterity and tend by their multiplication and extension to degrade the race. This inattention to breed is not, however, of so much consequence in the people, as in the rulers; in those to whom the destinies of nations are intrusted; on whose qualities and actions depend the present and future happiness of millions. Here, unfortunately, the evil is at its height; laws, customs, prejudices, pride, bigotry, confine them to intermarriages with each other; and thus degradation of race is added to all the pernicious influences inseparable from such exalted stations. . . The strongest illustration of these principles will be found in the present state of many royal houses in Europe.25 In addition to artificial selection, Lawrence also had a clear grasp of sexual selection in man, although he did not apply this to animals as Darwin later did in The Descent of Man. Lawrence saw sexual selection as an extension of the principles of animal breeding which might be applied to man: Connexions in marriage will generally be formed on the 23. Lawrence, Lectures, pp. 393-394. 24. Darlington, Darwin's Place, p. 20; Peter G. Mudford, "William Lawrence and The Natural History of Man," J. Hist. Ideas, 29 (1968), 435. Both of these authors indicate that Lawrence's political views added to the criticism of his book. 25. Lawrence, Lectures, pp. 394-395.

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idea of human beauty in any country; an influence, this, which will gradually approximate the countenance towards one common standard. If men, in the affair of marriage, were as much under management as some animals are in the exercise of the generative functions, an absolute ruler might accomplish, in his dominions, almost any idea of the human form. The great and noble have generally had it more in their power than others to select the beauty of nations in marriage: and thus, while, without system or design, they gratified merely their own taste, they have distinguished their order, as much by elegant proportions of person, and beautiful features, as by its prerogatives in society.26 Very little has been written on Lawrence's views on heredity and variation, but what has been written generally misinterprets his ideas. Many recent accounts of Lawrence draw heavily on C. D. Darlington's highly inaccurate Darwin's Place in History, in which the author states that Lawrence discussed "the processes of evolution" and applied them to man.27 Furthermore, Darlington implies that Lawrence saw direction in evolution determined by "competition or selection."28 Yet, as is clearly shown by the numerous passages from Lawrence which have been quoted above, Lawrence was not an evolutionist, although many of his ideas suggest elements of the Darwinian-Mendelian synthesis. Peter Mudford's recent critique of Darlington's book has exposed some of the major errors, but it does not examine Lawrence's ideas in detail.29 Darlington is not alone, however, in his misinterpretation of Lawrence. Conway Zirkle, in his excellent history of the concept of natural selection, states that Lawrence "almost arrived at an explanation of evolution through the action of natural selection and . . . just failed to make the ultimate logical inference."30 This statement, as well as Darlington's, fails to recognize the fact that an essential element of natural selection was missing 26. Ibid., pp. 389-390. Lawrence's remarks on sexual selection are taken almost verbatim from Samuel Stanhope Smith's Essay, pp. 116-117 (see n. 15 above). Smith's Essay is cited by Lawrence, Lectures, pp. 113, 443, 450, 451. 27. Darlington, Darwin's Place, p. 21. 28. Ibid., p. 17. Darlington also discusses the British anthropologist, James Cowles Prichard, in this context, since he expressed views similar to Lawrence's. The relationship between Lawrence and Prichard will be discussed in the final section of this paper. 29. Mudford, "William Lawrence and The Natural History of Man," pp. 430-436. 30. Zirkle, "Natural Selection. . ." (n. 4 above), p. 109.

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Sir William Lawrence from Lawrence's book, namely, the struggle for existence. Nowhere was any hint of this concept mentioned, nor is there any reason why it should have been. For Lawrence was concerned not with the evolution and adaptations of animals in nature, but with race formation in man. His analogy between variations in man and in domesticated animals was used to prove that all men are of one species. Variations in wild animals did not concern him, and, in any case, he believed wild animals to be much less variable than domesticated ones. Furthermore, Lawrence seems to have had no conception of the adaptations of animals to particular environments, and he certainly had no idea that some variations might make certain individuals more perfectly adapted to their environments than others. Therefore, while Lawrence realized that spontaneous variations could be preserved by breeding of similar individuals and exclusion of others, he had no explanation of why the preservation of certain characters in the races of man. He did hint that it would be possible for races to be formed through geographical isolation or sexual selection, but he was careful to point out that this was not necessarily the way that the present races actually were formed. As he put it, If, however, we should carry ourselves back, in imagination, to a supposed period, when mankind consisted of one race only,-and endeavor to show how the numerous varieties, which now occupy the different parts of the earth, have arisen out of the common stock, and have become so distinct from each other, as we find them at present-we cannot arrive at so satisfactory a decision.3' Thus it is clear that there was no reason for Lawrence to make the "logical inference" of evolution. Merely denying the inheritance of acquired characteristics, even when a theory of spontaneous variation is substituted, does not lead inevitably to evolution, for there is no direction given to such variation, nor is there any reason why it should transcend specific boundaries. Without the concept of natural selection, Lawrence had every reason to believe that variations in wild animals would be swamped and would return to the original type. It is true that he seems to have had some understanding of the role of geographical isolation and sexual selection in forming new races, but since he was not a traveling naturalist, he had no reason to apply these processes to animals in nature. If Lawrence did not anticipate Darwinian evolution, and was 31. Lawrence, Lectures, p. 470.

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therefore not a "medical evolutionist," as Darlington calls him,32 then what position does he occupy in the history of nineteenthcentury biology? What role did a man whose ideas on heredity seem so far ahead of his time play in the development of biological thought in the decades before Darwin? I will discuss this problem from two points of view. First I will deal with the reception of Lawrence's ideas, both by the popular press and the scientific community. Then I will examine in detail the development of Lawrence's own ideas on heredity and variation, so that we may better understand his position in nineteenthcentury science. THE RECEPTION OF LAWRENCE'SIDEAS As has been mentioned already, Lawrence's Lectures were engulfed in a storm of controversy which grew to such proportions that he was forced to suppress his book. The reasons for the denunciation of Lawrence are numerous and complex, and they have been treated extensively by a number of authors.33 Most of the opposition was connected with his views on the nature of life, on the function of the brain, and on the nature of scientific enquiry, together with his religious and political leanings. Edward Grinfield, for example, in a pamphlet entitled Cursory Observations Upon the 'Lectures' . . . by W. Lawrence, accused Lawrence of being a materialist, denying biblical Scripture, being anticlerical, praising the Quakers, distorting ancient history, and favoring American democracy over the British government.34 Darlington is quite incorrect in implying that Lawrence was attacked primarily because he discussed the evolution of man.35 Yet, despite the fact that he did not even discuss evolution, there were a number of criticisms of Lawrence's work, which, although peripheral to the main issues, foreshadowed some of the objections raised against Darwinian evolution forty years later. Much of the attack on Lawrence focused on his advocacy of the materialistic views of the French physiological school and was part of the general English reaction against French science 32. Darlington, Darwin's Place, p. 23. 33. See n. 5 above. 34. Edward W. Grinfield, Cursory Observations Upon the "Lectures on Physiology, Zoology, and the Natural History of Man, Delivered at the Royal College of Surgeons, by W. Lawrence, F.R.S." in a Series of Letters Addressed to that Gentleman; With a Concluding Letter to His Pupils. 2nd ed. (London: Cadell & Davies, 1819), pp. 5-8, 48, 52. 35. Darlington, Darwin's Place, pp. 19-24.

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Sir William Lawrence in the period following the Revolution of 1789.36 In evolutionary biology, the same anti-Jacobinism had resulted in vigorous denunciations of the doctrines of Lamarck, as well as those of Erasmus Darwin.37 Lawrence was already suspect in the eyes of many Englishmen because of his connections with the physiology of the French materialists, and some reviewers found ideas in Lawrence's book which seemed to them to hint at the evolutionary views of Lamarck and Erasmus Darwin. Many reviewers felt that Lawrence's notion that the human brain functioned on principles identical to those of animal brains was dangerously close to asserting that man was in fact no more than an animal. Lawrence had written, "The number and kind of the intellectual phenomena in different animals correspond closely to the degree of development of the brain."38 Similarly, "It is strongly suspected that a Newton or a Shakespeare excels other mortals only by a more ample development of the anterior cerebral lobes, by having an extra inch of brain in the right place." 39 The Quarterly Review for July 1819 complained that the materialists, including Lawrence, believed "there is no other difference between a man and an oyster, than that the one possesses bodily organs more fully developed than the other." The reviewer then went on to show that this was only a short step away from the pernicious doctrines of Erasmus Darwin. "Dr. Darwin, indeed, carried the hypothesis still farther-for it was a favorite part of his creed that man, when he first sprang by chance into being, was an oyster, and nothing more." 40 The reviewer was surprised that Lawrence had rejected the man-asorangutang theories of Monboddo and Rousseau, since he clearly believed that in intellectual qualities "man is nothing more than an orang-outang or ape with more 'ample cerebral hemispheres."' 41 As to the question of why Mr. Lawrence maintained such opinions, the reviewer could only conclude "that he is impelled to these speculations by having some extra inch of brain in the wrong place."42 The attack on Lawrence was not confined to Great Britain. On 36. Temkin, "Basic Science" (n. 5 above), pp. 103-105. 37. Norton Garfinkle, "Science and Religion in England 1790-1800: The Critical Response to the Work of Erasmus Darwin," J. Hist. Ideas, 16 (1955), 376-388. 38. Lawrence, Lectures, p. 98. 39. Ibid., pp. 99-100. 40. George D'Oyly, "Abernethy, Lawrence, etc. on the Theories of Life," Quarterly Review, 22 (July 1819), 14. 41. Ibid., pp. 29-30. 42. Ibid., p. 22.

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the other side of the Atlantic, the North American Review published a highly critical review of Lawrence's book. Noting that "none but a philosopher mistakes a man, however humble his intellect, for an improved variety of monkey," the reviewer asked "whether it is philosophical or natural to conclude that those [mental] faculties . . . are but the active state of organs, which he has so nearly in common with orang-utans, pongos, monkeys, and the rest of the tribe of disgusting caricatures of the human species." 43 The reviewer also objected to Lawrence's use of phrases which no doubt suggested the "development hypothesis" of Lamarck: We take occasion here to express our annoyance at the frequent recurrence of the words 'develop' and 'development' in this work . . . We can assure Mr. Lawrence and some other modern writers, that to tell us that the tail of an animal is long, or his teeth large, would be quite as intelligible and a great deal more agreeable, than to say that these appendages were more developed.44 Leaving aside the question of thought and the brain, there were many who objected to the use of analogies with domesticated animals to explain the varieties of man. Edward Grinfield said that attempts to characterize man as an animal "will always appear ludicrous to those who are not initiated into the art of degrading their own species."45 As late as April 1850, the Democratic Review criticized "Laurence, La Marck, and others" for attempting "to account for existing differences [in human races] on the ground of the operation of various causes acting through long periods of time, gradually transmuting man into the various species as we now find him." 46 In the July 1850 issue, the Democratic Review praised the Reverend Thomas Smyth for seeking the laws of human nature in the "passions, social habits, laws, customs, arts, literature, [and] sciences." The reviewer continued: How different from the conceptions of Blumenbach, and his pupils, Lawrence and Prichard? How intensely interesting does it become, thus treated, compared with the dry, abstract, and uninteresting technicalities of the dissecting-table, and 43. "Lawrence's Lectures on Physiology, Zoology, and the Natural History of Man," North American Review, 17 (1823), 23-24. 44. Ibid., p. 19. 45. Grinfield, Cursory Observations, p. 28. 46. "Natural History of Man," United States Magazine and Democratic Review, 26 (April 1850), 334.

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Sir William Lawrence the debasing association with vegetables and beasts, as analogues of human nature.47 The August 1850 Democratic Review continued the attack, and once again, the use of animal analogies was criticized; as for the frequent use of such analogies as are now in vogue by grave philosophers, and the use of which has conferred on some of them a degree of reputation which, ordinarily, can be gained only by men of real genius . . . we confidently predict that ten years will not have elapsed before it will be regarded with . . . contempt.48 In fact, ten years had not passed before Darwin's Origin of Species provided the basis for the study of man as an animal. One of the most interesting attacks on Lawrence's theory of race formation appeared in Robert Knox's The Races of Men, published in 1850. Although Lawrence was not named, it is clear which theory Knox was discussing. Knox rejected the domesticated animal analogy, for "man is not a ruminant."49 As for the ancon sheep, Knox said, "When I am told that there is a short-legged race of sheep somewhere in America, the product of accident, my reply is simply, I do not believe it."50 Knox thus raised an objection against the theory of race formation by spontaneous variation that is similar to objections expressed against evolution by natural selection ten years later, namely, that all is reduced to blind chance. In his discussion, Knox failed to distingush between this type of variation and the inherited effects of climate. It is the old fable of Hippocrates and the Macrocephali reduced to something like a scientific formula; transferred from sheep, it has been made the basis of a theory of race, of mankind reducing all to accident. By accident, a child darker than the rest of the family is born . . . This dark child, a little darker than the other, separates, with a few more, from the rest of the family, and sojourns in a land where a hot sun enbrowns them with a still deeper hue. In time they become blacker and 47. 41-43. 48. 1850), 49. 1850), 50.

"Natural History of Man," U.S. Mag. and Dem. Rev., 27 (July, 1850), "Natural History of Man," U.S. Mag. and Dem. Rev., 27 (August 140. Robert Knox, The Races of Men (Philadelphia: Lea & Blanchard, p. 67. Ibid., pp. 67-68.

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blacker, or browner and browner . . . This is ancient and modem physiology I5Knox seems to have realized that if this theory of accidental variation were accepted, there might be no barrier to contain variation within the species. Of accidental variation, he said, "May it not be that such is simply a law of nature?" He then went on to wonder whether these variations might really be the origin of new races if isolated and bred, adding, "Hence on this view has been explained the origin of permanent varieties, as they are called, which I fear is just another name for species." 52 William Van Amringe expressed similar fears that Lawrence's use of animal analogies to explain variation in human races was a victory in disguise for the "progressive developists." Recent writers imagine they have done much for the honor of the race, by placing [man] in an Order by himself,-thus separating him from the debasing association of monkeys, lemurs, and bats. It amounts, however, only to a nominal honor; a promotion without advantage; a distinction without a separation. They have, nevertheless, kept man so closely associated, not only with the anthropoid animals . . . but with the whole of organic nature . . . that everything having life is regarded as his analogue, his associate, in the highest and noblest properties of his nature. Progressive developists could ask for no more. They gained the fruits of victory, if they lost the battle. Horses and asses, oxen and sheep, dogs and hogs, rabbits and poultry, &c. constitute the basis of all theories, of all arguments, of all conclusions, in relation to the highest and noblest attributes of Man.53 Van Amringe argued that the human races were originally distinct, and he agreed with Lawrence that climate could not have produced the varieties of the human species. Indeed, he quoted Lawrence's own arguments against the environmentalist theories, stating that Lawrence "always argues well, until he arrives at the point from whence species are to be inferred." 54 Having used Lawrence's arguments against climatically pro51. Ibid., pp. 67-68. 52. Ibid., p. 113. 53. William Frederick Van Amringe, An Investigation of the Theories of the Natural History of Man by Lawrence, Prichard, and Others (New York: Baker & Scribner, 1848), pp. 26-27. 54. Ibid., pp. 240-243.

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Sir William Lawrence duced variations, Van Amringe then went on to reject "all theories founded upon accidental, unnatural, or monstrous births being the progenitors of any permanently distinct race of men or animals." 55 Accidental births could not give rise to permanent varieties because "their defective constitutions are incapable of continuing their kind; or if their constitutions are vigorous, they speedily return to, and are lost in, their original type." 5ff Finally, Van Amringe criticized Lawrence on the grounds that his theory required "innumerable intermediate" changes to have occurred between white and black races of man, and these intermediate forms were not observable in nature. Once again, we see an anticipation of objections later raised against Darwin's theories: It probably did not occur to the learned Lecturer, that he was not supported by the analogy of domestic animals for these "almost innumerable intermediate" changes, which must occur from a change of color from white to black; consequently, it amounted to an abandonment, in this respect, of his analogies, which constitute the foundation of his theory . . . A white domestic animal, in changing to a black variety, does not proceed by "almost innumerable intermediate changes" . . . but passes from white to black, red, pied, brindled, &c. as it were by leaps. Consequently the analogy fails to apply, and the theory of the human species from this cause also.57 Not all of the reactions to Lawrence's Lectures were negative. The American Quarterly Review for June 1828 published a rather favorable review of the work. The reviewer felt that the zoological study of man had been neglected and that Lawrence's book "may be considered as going far towards filling the void in [that] department of natural history." 58 Lawrence's theory of spontaneous variation was believed to be more in agreement with observed fact than the theory of climatically induced variations. Interestingly enough, the reviewer argued that if the inherited effects of climate were accepted, then one must accept the "fanciful hypothesis" of Lamarck.59 Although he believed there was too little evidence on which to base any theory of the origin of variations, the reviewer noted that the examples of albinos and 55. Ibid., p. 424. 56. Ibid., p. 426. 57. Ibid., p. 443. 58. "Lawrence's Lectures on Physiology, Zoology, and the Natural History of Man," American Quarterly Review, 3 (June 1828), 341. 59. Ibid., p. 333.

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"porcupine men" were good evidence for the occurrence of accidental varieties.60 Throughout the review, the author argued in favor of freedom of scientific enquiry and praised Lawrence for his courage in expressing unpopular views, although the author did not necessarily agree with them. He was critical of the way in which Lawrence had been treated.6' Here and there, other defenses of Lawrence and the freedom of scientific enquiry appeared in the press. The Monthly Magazine for June 1, 1819, compared Lawrence to Galileo and expressed the hope that an exposure of the affair by a free press would aid the search for truth.62 Other periodicals, like the North American Review, criticized the treatment Lawrence had received, not because of a love of free scientific enquiry, but because the notoriety which his book acquired caused it to be "hawked at the corners of the streets in sixpenny numbers," thus spreading its pernicious influence.63

It is evident from the foregoing discussion that Lawrence's book had an impact on the general public and the popular press which persisted, at least occasionally, for more than thirty years. While it is true that the overwhelming bulk of the criticism of Lawrence was leveled at his physiological theories of life and mind, nevertheless his views hinting at the problem of evolution were also discussed. The question which remains is this: to what extent did Lawrence's views, particularly on variation and heredity, affect the scientific community? Were his ideas on the formation of permanent varieties simply lost sight of, or did they have any direct effect on the formulation of evolutionary theories? Several early writers who recognized the advanced nature of Lawrence's views have assumed that his influence was lost.64 In the following section, I intend to show that this was not the case, that his book was widely read by prominent figures in the development of evolutionary theory, and that it had a considerable impact on several of them. LAWRENCE AND THE EVOLUTIONISTS The extent of Lawrence's influence on Charles Darwin is difficult to determine. Darwin was aware of Lawrence's book as 60. Ibid., p. 335-337. 61. Ibid., pp. 326-328. 62. The Monthly Magazine, 47 (London, 1819), 451. 63. North American Review (1823), p. 14. 64. E. W. Count, This is Race (New York: Schuman, 1950), p. 706; Cunningham, "Anthropology in 18th Century" (n. 4 above), pp. 30-34; Hutchinson, "In Memory of Lawrence" (n. 4 above), pp. 200-201.

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Sir Wflliam Lawrence early as 1838, for in his second notebook, which covers the period from February to July of that year, there is a notation on structural differences among human races. Here Darwin reminded himself to "make abstract on this subject from Lawrence, Blumenbach, and Prichard."65 In the same notebook there is a list of books "to be read," which includes a reference to Lawrence.66 However, Darwin does not seem to have read Lawrence's book until April 23, 1847, or at least if he read it before this, there is no indication of it in his notebooks.67 According to Sydney Smith, Darwin had a copy of Lawrence in his library, but unlike many of his books, it has no annotations in the text. Next to the title in his reading list, Darwin wrote, "Poor."68 It therefore appears that Darwin was not impressed by Lawrence's discussion of heredity and variation, or his denial of the inheritance of aquired characteristics. The reason for this is probably that he read it too late. By 1847, Darwin's theory of evolution by natural selection was relatively complete, and he had already written his two preliminary sketches for the Origin of Species. By this time, Darwin's knowledge of variation in domesticated animals, as well as in wild animals, was far greater than anything to be found in Lawrence. In his early notebooks of 1837 and 1838, Darwin had considered the isolation of major saltations, or sports, to be an important mechanism of evolution. However, after his discovery of the principle of natural selection, the role of sports and isolation in the production of new species gradually became less important in Darwin's mind.69 Therefore, he was probably not impressed with a book which held fast to the fixity of species and added little to his understanding of variation. On one problem, however, Darwin may have been influenced by Lawrence. This was the problem of sexual selection in man. I have already noted Lawrence's clear grasp of this concept, and his implied application of it to race formation. I have also quoted passages in which Lawrence attributed the beauty of the nobility to selection of the most attractive women for wives. The only references to Lawrence which I have found in any of Darwin's works occur in the section on sexual selection in The Descent of 65. Gavin De Beer, ed., "Darwin's Notebooks on Transmutation of Species: Part II. Second Notebook (February to July 1838)," Bull. Brit. Mus. Nat. Hist., Historical Series, vol. 2, no. 3 (1960), p. 107. 66. Ibid., p. 115. 67. Sydney Smith, "The Origin of 'The Origin,"' The Advancement of Science, 16 (1960), 399. 68. Ibid., p. 399. 69. Olby, Origins of Mendelism, pp. 55-58.

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Man. In one footnote, Darwin referred to "Lawrence . . . who attributes the beauty of the upper classes in England to the men having long selected the more beautiful women." 70 What is even more interesting is Darwin's treatment of human race formation. He examined the possibility that direct action of the climate might have produced differences in skin color, and while he admitted that some inherited effects might be produced, he believed that this had been a minor factor.7' Similarly, he saw the effects of use and disuse of organs as quite insignificant in producing racial differences.72 Darwin then suggested that perhaps natural selection had produced racial differences among men, but he said that "we are at once met by the objection that beneficial variations alone can be thus preserved." He was unable to see how the various distinguishing racial characteristics could be beneficial.73 Darwin finally concluded that there was "one important agency, namely Sexual Selection, which appears to have acted powerfully on man." To this agency, he suggested, could be ascribed differences in "color, hairiness, form of features, etc." 74 Nevertheless, while he offered this as a suggestion, he was forced to admit, as was Lawrence, that the causes of racial differences were largely unknown. All he was sure of was that they were probably due to the preservation of spontaneous variations: I do not intend to assert that sexual selection will account for all the differences between the races. An unexplained residuum is left, about which we can only say, in our ignorance, that as individuals are continually born with, for instance, heads a little rounder or narrower, and with noses a little longer or shorter, such slight differences might become fixed and uniform, if the unknown agencies which induced them were to act in a more constant manner, aided by long-continued intercrossing. Such variations come under the provisional class alluded to in our second chapter, which for the want of a better term are often called spontaneous.75 How much these ideas were influenced by Lawrence, and how much they were derived independently from Darwin's own theories, is impossible to say at this point. However, it is clear 70. Charles Darwin, The Descent of Man (New York: Hurst & Co., 1874), p. 610n; Other references to Lawrence: pp. 49n, 581n, 597n, 604n, 606n. 71. Darwin, Descent, p. 212. 72. Ibid., p. 213. 73. Ibid., p. 214. 74. Ibid., pp. 214-215. 75. Ibid., p. 215.

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Sir William Lawrence from Darwin's footnotes that he consulted Lawrence's book when writing the section on sexual selection. Furthermore, as early as 1864, he had written to Wallace, "I suspect that a sort of sexual selection has been the most powerful means of changing the races of man," adding, "Our aristocracy is handsomer . . than the middle classes, from pick of women." 76 Finally, it is worth noting that Darwin expressed views on the application of breeding to man, which, if not actually influenced by Lawrence's ideas, were at least strikingly similar. Thus, Darwin wrote, *

Man scans with scrupulous care the character and pedigree of his horses, cattle, and dogs before he matches them; but when he comes to his own marriage he rarely, or never, takes any such care . . . Yet he might by selection do something not only for the bodily constitution and frame of his offspring, but for their intellectual and moral qualities. Both sexes ought to refrain from marriage if they are in any marked degree inferior in body or mind; but such hopes are Utopian, and will never be even partially realized until the laws of inheritance are thoroughly known.77 If Darwin was influenced only slightly, if at all, by Lawrence's book, the same cannot be said of the co-discoverer of natural selection, Alfred Russel Wallace. An examination of Wallace's published letters and writings suggests that Lawrence had a considerable influence on his thinking, an influence which has hitherto been largely overlooked. In a letter to Henry Walter Bates, written on December 28, 1845, Wallace discussed his impressions of the Vestiges of the Natural History of Creation.78 In the same letter, which clearly shows that Wallace was speculating on the origin of species at this early date, Lawrence's book was specifically mentioned: I have rather a more favorable opinion of the "Vestiges" than you appear to have. I do not consider it as a hasty generalization, but rather as an ingenious hypothesis strongly supported by some striking facts and analogies but which remains to be proved by more facts & the additional light 76. James Marchant, Alfred Russel Wallace: Letters and Reminiscences (New York: Harper & Bros., 1916), p. 128. 77. Darwin, Descent, p. 642. 78. H. Lewis McKinney, "Wallace's Earliest Observations on Evolution: 28 December 1845," Isis, 60 (Fall 1969), 370-373. I have used the original text of the letter, as given by McKinney, in my quotations. It was published in slightly abridged form in A. R. Wallace, My Life (New York: Dodd, Mead, & Co., 1905), I, 254-255, and in Marchant, A. R. Wallace, pp. 73-74.

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which future researches may throw upon the subject. It in all events furnishes a subject for every observer of nature to turn his attention to; every fact he observes must make either for or against it, and it thus furnishes both an incitement to the collection of facts & an object to which to apply them when collected. I would observe that many eminent writers give great support to the theory of the progressive development of species in animals and plants. There is a very interesting and philosophical work bearing directly on the subject "Lawrence's Lectures on Man" delivered before the Royal College of Surgeons and which are now published in a cheap form.79 Wilma George and H. Lewis McKinney both quote from this letter in their discussions of Wallace, yet each of these authors includes only the portion dealing with the Vestiges and omits the reference to Lawrence.80 Barbara Beddall mentions the fact that Wallace read Lawrence, but she leaves it at that.81 Maurice Mandelbaum hints that Lawrence may have influenced Wallace but does not discuss this in detail.82 If Wallace had simply stated that Lawrence's book was a "work bearing directly on the subject" of the development of species and said no more, it would be difficult to assess Lawrence's influence on Wallace. However, Wallace summarized Lawrence's views at some length, before giving his own interpretation of the phenomena which Lawrence described. The passage is worth quoting in full: The great object of these lectures is to illustrate the different races of mankind & the manner in which they probably originated-and he arrives at the conclusion, as does also Mr. 79. McKinney, "Wallace's Earliest Observations" (n. 78 above), p. 370. 80. Wilma George, Biologist Philosopher: A Study of the Life and Writings of Alfred Russel Wallace (New York: Abelard-Schuman, 1964), 10; H. Lewis McKinney, "Alfred Russel Wallace and the Discovery of Natural Selection," J. Hist. Med. and Allied Sci., 21 (1966), 337. Since this section was written, I have discovered that McKinney does quote the portion of the letter relating to Lawrence in his Ph.D. thesis. However, he does not discuss any influence of Lawrence's ideas on variation on Wallace. See H. Lewis McKinney, "Alfred Russel Wallace and the Discovery of Natural Selection," unpubl. diss. (Ithaca, N.Y.: Cornell University, 1967), pp. 213-214. 81. Barbara Beddall, "Wallace, Darwin, and the Theory of Natural Selection," J. Hist. Biol., 1 (Fall 1968), 266. 82. Maurice Mandelbaum, "Scientific Background of Evolutionary Theory in Biology," in Philip P. Wiener and Aaron Noland, Roots of Scientific Thought (New York: Basic Books, 1957), p. 532.

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Sir William Lawrence Pritchard in his work on the Physical history of man, that the varieties of the Human race have not proceeded from any external cause but have been produced by the development of certain distinctive peculiarities in some Individuals which have become propagated through an entire race. Now I should say that a permanent peculiarity not produced in any way by external causes is a distinction of species and not of mere variety & thus if the theory of the "Vestiges" is carried out the "Negro" the red Indian & the European are distinct species of the genus Homo. The Albino which presents as striking a difference as the negro, we have modern and not uncommon instances of the production of, but the peculiarity is not propagated so extensively as that of the other varieties. Now it appears to me that the "Albino" and "negro" are very analogous to what are generally considered as "variety" and "species" in the animal world. An animal which differs from another by some decided and permanent character however slight which difference is undiminished by propagation and unchanged by climate and external circumstances, (like the negro) is invariably considered as a distinct species-while one which is not propagated so as to form a distinct race, but is produced more frequently from the parent stock (like the Albino) is generally if the difference is not very striking, considered a variety,-now I consider both these to be equally distinct species, & I would only consider those to be varieties whose differences are produced by External causes & which are not propagated as a distinct race. In how many cases in the animal world & particularly among Insects are the differences between species far less than those between varieties, so consid[ere]d neither however being produced by External circumstances. How well too does this theory account for those excessively rare species whose Existence seems almost a mystery. They may be produced by more common species at intervals in the same manner as the Albino is from European Parents. Read Lawrence's work-it

is well worth it.83

There are several important points to be made in connection with Wallace's letter. First of all, Wallace clearly was impressed by Lawrence's idea that spontaneous rather than acquired variations have given rise to new races. While Wallace did not state 83. McKinney, "Wallace's Earliest Observations," pp. 372-373.

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specifically that acquired characteristics are not inherited, he implied it when he said that differences produced by external circumstances "are not propagated as a distinct race." Unlike Lawrence, Wallace imposed no limits on variation. What Lawrence considered to be permanent varieties, Wallace called species. It has generally been assumed that Wallace was converted to evolution through his reading of the Vestiges. Yet it seems clear from his 1845 letter that while he may have gotten the initial idea of evolution from the Vestiges, he was quite possibly even more impressed with Lawrence's ideas on variation and race formation. Thus, it appears that at the very beginning of his speculations on evolution, Wallace had found in Lawrence a possible mechanism of organic change, that of spontaneous variations leading to the formation of new species. In fact, Wallace actually made this extension from Lawrence's ideas when he said, in the passage quoted above, "How well too does this theory account for those excessively rare species whose Existence seems almost a mystery. They may be produced by more common species at intervals in the same manner as the Albino is from European Parents." What Wallace lacked at this point ,and what Lawrence had lacked as well, was a mechanism to preserve variation and give direction to evolution. By 1858, Wallace had, of course, found that mechanism to be natural selection. In contrast to Darwin, Wallace never seems to have ascribed much importance to the inheritance of acquired characteristics. He continued to believe that spontaneous variations provided the raw material for natural selection.84 In his "Species Notebook," quoted by Beddall, Wallace wrote, "We have no proof how the varieties of dogs were produced. All varieties we know of are produced at birth, the offspring differing from the parent. This offspring propagates its kind." 85 In other passages from his "Species Notebook," Wallace was somewhat uncertain on the question of the inheritance of acquired characteristics. In an entry made in July 1856, he wrote: "Acquired variations. (? Are these ever propagated) Yes." 86 In 1857, he wrote of plants which "by the difference of stations of nourishment and of soil produce varieties."87 However, in a letter to Darwin in 1857, now apparently lost, Wallace evidently minimized the effects of climate on variation, for in his reply, Darwin said, "I most entirely agree 84. (n. 81 85. 86. 87.

George, Biologist Philosopher, p. 76; Beddall, "Wallace and Darwin" above), p. 290. Beddall, "Wallace and Darwin," p. 283. McKinney, "Alfred Russel Wallace . . ." (n. 80 above), p. 84. Ibid., p. 101.

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Sir William Lawrence with you on the little effect of 'climatic conditions' which one sees referred to ad nauseam in all books: I suppose some very little effect must be attributed to such influences, but I fully believe that they are very slight." 88 Although Wallace accepted Darwin's pangenesis theory of heredity when it first appeared in 1868, he later became an enthusiastic proponent of Weismann's theory of the non-inheritance of acquired characteristics.89 Yet even before Weismann, Wallace was consistent in maintaining the existence of random variations. In a review written in 1868, he said, "Universal variability-small in amount, but in every direction, ever fluctuating about a mean condition until made to advance in a given direction by 'selection,' natural or artificial-is the simple basis for the indefinite modification of the forms of life." 90In Darwinism, published in 1889, Wallace vigorously denied the importance of use and disuse of organs, the direct effect of climate, and other acquired variations, and he buttressed his argument with evidence from Galton and Weismann. He stressed the absolute importance of natural selection in directing evolution.9' It seems possible that Wallace's attitude toward the inheritance of acquired characteristics was at least partly the result of his early reading of Lawrence's book. It is significant that both Lawrence and James Cowles Prichard, to whom Wallace also refers in his 1845 letter, were concerned with the origin of human races.92 McKinney has argued that "Wallace was led to his great discovery by a consideration of the origin of human races fiTSt before transferring to the animal species." McKinney speculates that it may have been his interest in ethnology which led Wallace to recall passages he had read in Malthus' Essay on Population, passages which provided the key to his theory.93 As shown by the 1845 88. Marchant, A. R. Wallace, p. 108. 89. George, Biologist Philosopher, pp. 76-77. 90. Alfred Russel Wallace, "Creation by Law," in Natural Selection and Tropical Nature (London: MacMillan, 1895), p. 158. 91. Alfred Russel Wallace, Dar-winism (London: MacMillan, 1889), pp. 410-444. 92. James Cowles Prichard, Researches Into the Physical History of Man, 1st ed. (London: John and Arthur Arch, 1813); Researches Into the Physical History of Mankind, 2nd ed., 2 vols. (London: John and Arthur Arch, 1826); 3rd ed., 5 vols. (London: Sherwood, Gilbert & Piper, 18361847). It is unclear which edition Wallace read. The first and second contain ideas similar to Lawrence's; the third was changed considerably. See the final section of this paper for the relationship between Lawrence and Prichard. 93. McKinney, "Wallace and . . . Natural Selection," J. Hist. Med. (1966), p. 355 (see n. 80 above).

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letter to Bates, the link between Wallace's ethnological and evolutionary interests was forged before he began his travels. It now seems clear that his reading of Lawrence and Prichard was the principal reason for this link. Indeed, it is quite likely that his reading of Lawrence and Prichard marked the beginning of his interest in ethnology, which, if McKinney is correct, eventually led indirectly to the discovery of natural selection.94 An interesting intermediate link between the views of Lawrence and those of Wallace and Darwin occurs in the writings of Edward Blyth. Loren Eiseley has discussed in detail the important impact which he feels Blyth had on Darwin.95 McKinney has found that Wallace made notes on Blyth's paper of 1835 (see below). Wallace later referred back to these notes when writing a "Note on the Theory of Permanent and Geographical Varieties" in 1858.96 It thus appears that Blyth was an important source of ideas for Wallace as well as Darwin. However, despite the apparent importance of Blyth's work, no attempt has yet been made to examine in detail the origins of Blyth's own ideas. In 1835, Blyth published a paper entitled "An Attempt to Classify the 'Varieties' of Animals."97 In this article, Blyth attempted to clarify the use of the term "variety," which he said had previously been used to denote everything from "the slightest individual variation" to "the most dissimilar breeds." Blyth discussed two types of varieties which differed only in degree, "simple variations" and "true varieties." The former were "slight individual variations . . . unaccompanied by any remarkable structural deviation."98 As an example of a "simple variation," Blyth cited the phenomenon of albinism. Blyth followed Lawrence in concluding that these variations could be perpetuated only if selectively bred: Mr. Lawrence observes on the subject (in his Lectures on the Physiology, Zoology, and the Natural History of Man) "the disposition to change is generally exhausted in one individual, 94. McKinney makes no mention of Lawrence or Prichard in his published paper, but in his thesis, he notes Wallace's high praise for Lawrence and suggests Lawrence's view of man as an animal may have led Wallace to make the connection between human races and animals species. See McKinney, "Alfred Russel Wallace" (n. 80 above), pp. 129-130. 95. Loren Eiseley, "Charles Darwin, Edward Blyth, and the Theory of Natural Selection," Proc. Amer. Phil. Soc., 103 (1959), 94-158. 96. McKinney, "Alfred Russel Wallace" (n. 80 above), p. 108. 97. Edward Blyth, "An Attempt to Classify the Varieties of Animals," Magazine of Natural History, 8 (1835), 40-53; reprinted in Eiseley, Proc. Amer. Phil. Soc., 103 (1959), 115. All subsequent page references are to the reprint in Eiseley. 98. Blyth (1835), in Eiseley, Proc. Amer. Phil. Soc., 103, p. 116.

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Sir William Lawrence and the characters of the original stock return, unless the variety is kept up by the precaution above mentioned, of excluding from the breed all which have not the new characters" . . . These observations apply alike to all simple or individual variations, and to most other varieties, and afford one of the many reasons why marked breeds are in a state of nature so rarely perpetuated.99 Similar to "simple variations" were "true varieties," which included "deformities" and "monstrous births." These were the familiar sports observed by all animal breeders. Blyth cited the ancon sheep as an example. His description was obviously taken from Lawrence, to whom he referred in a footnote.100 Like "simple variations," "true varieties" were seldom perpetuated in nature. However, Blyth did note that "deviations of this kind do not appear to have any tendency to revert to the original form: this, most probably, could only be restored, in a direct manner, by the way in which the variety was first produced." 10o Blyth thus had a rather crude conception of what would today be considered reverse mutation. Blyth clearly interpreted these two types of varieties as spontaneous, as distinguished from "acquired variations." He generally followed Lawrence in denying the inheritance of acquired characteristics. In an article published in 1837, however, he seems to have allowed for the inheritance of acquired instincts in domesticated animals, but not in wild animals.102 Nevertheless, in his discussion of the varieties of the human species, he followed Lawrence quite closely, as the following passage shows: With regard to colour, we know that temperature exerts no permanent gradual influence whatever; white races remain unchanged at slight elevations within the tropics . . . the swarthy inhabitants of Mauritania are a white race, and their sunburnt hue is merely an acquired variation, which is not transmissible by generation.103 Races of man, Blyth concluded, have been formed in a manner 99. Ibid.,p. 116. 100. Ibid., p. 118. 101. Ibid. 102. Edward Blyth, "On the Psychological Distinction All Other Animals," Magazine of Natural History, n.s. 85, 131-141; reprinted in Eiseley, Proc. Amer. Phil. Soc., 103. Blyth (1835), in Eiseley, Proc. Amer. Phil. Soc.,

Between Man and 1 (1837), 1-9, 77103 (1959), p. 141. 103, pp. 118-119.

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analogous to the formation of the ancon breed of sheep, that is, through the perpetuation of spontaneous variations.104 As I have pointed out in my discussion of Lawrence's ideas, the mere denial of the inheritance of acquired characteristics does not necessarily lead to the concept of evolution, and, indeed, Blyth was not an evolutionist. He believed all variation was contained within specific boundaries, just as Lawrence did. By separating non-inheritable acquired variations from inheritable spontaneous variations, however, Blyth was able to show that only the latter could be the origin of breeds. These were established in domesticated animals by artificial selection: Breeds . . . are, for the most part, artificially brought about by the direct agency of man . . . When two animals are matched together, each remarkable for a certain given peculiarity, no matter how trivial, there is also a decided tendency in nature for that peculiarity to increase; and if the produce of these animals be set apart, and only those in which the same peculiarity is most apparent, be selected to breed from, the next generation will possess it in a still more remarkable degree.105 Thus Blyth recognized two important components of Darwinian evolution, random variation and selection, just as Lawrence had, and like Lawrence, he applied these principles to the origin of human races. Blyth was somewhat more "advanced" than Lawrence in his ideas of variation, for he distinguished between major saltations, or monstrous births, and smaller variations, '<nomatter how trivial." However, he undoubtedly did not conceive of these variations on a scale as small as the modern concept of mutations. Blyth also recognized a process operating in nature which was analogous to artificial selection. However, he believed it acted not to produce new breeds but to preserve the original species. "The original form of a species," he wrote, "is unquestionably better adapted to its natural habits than any modification of that form." 106 In the struggle for existence, the best adapted, or original form, would be naturally selected. In Blyth's words: Among animals which procure their food by means of their agility, strength, or delicacy of sense, the one best organised must always obtain the greatest quantity; and must, therefore, become physically the strongest, and be thus enabled, by 104. Ibid. 105. Ibid., pp. 117-118. 106. Ibid., p. 118.

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Sir William Lawrence routing its opponents, to transmit its superior qualities to a greater number of offspring. The same law, therefore, which was intended by Providence to keep up the typical qualities of a species, can be easily converted by man into a means of raising different varieties.'07 Eiseley has traced the roots of Blyth's ideas on the struggle for existence to Lyell's Principles of Geology. Like Blyth, Lyell recognized the conservative aspects of natural selection while failing to see its creative role in forming new species. Eiseley notes, however, that while Lyell made "vague references . . . to the effects of climate, temperature, and other similar factors, in determining organic change," Blyth "wrestles directly with the genetics of the problem." 108He quotes the following passage from Blyth by way of illustration: There would almost seem, in some species, to be a tendency, in every separate family, to some particular kind of deviation; which is only counteracted by the various crossings which, in a state of nature, must take place, and by the . . . law which

causes each race to be chiefly propagated by the most typical and perfect individuals.'09 The origins of Blyth's more "modem" ideas on genetics now seem clear. They were derived from ideas which he found in Lawrence, particularly the notion that spontaneous rather than acquired variations are what are important in the formation of breeds and races through selection. As if to dispell any further doubts we might have, Blyth actually listed his major sources: 'Dr. Pritchard's work on man . . . the published Lectures on the Natural History of Man, by Lawrence . . . the second volume of Lyell's Principles of Geology." 'lo Gillispie has stated that Darwin was the first to make a distinction between the origin and preservation of variations."' Yet even before Darwin, Lawrence and Prichard made this distinction partially through their denial of the inheritance of 107. Ibid. 108. Eiseley, "Darwin and Blyth," p. 105. 109. Ibid., p. 105. 110. Blyth (1835), in Eiseley, Proc. Amer. Phil. Soc., 103, p. 119; Blyth read either the first (1813) or the second (1826) edition of Prichard's Researches, since publication of the third edition was not started until 1836 (see n. 92 above). In both editions, Prichard denied the inheritance of acquired characteristics. The 1826 edition contains views on natural selection similar to Blyth's. 111. C. C. Gillispie, "Lamarck and Darwin in the History of Science," in Forerunners of Darwin, ed. by Bentley Glass, et. al. (Baltimore: Johns Hopkins Press, 1959), p. 287.

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acquired characteristics. The origin of variations was spontaneous; their preservation was insured by selective breeding or isolation. Blyth advanced somewhat further in his recognition of the conservative aspect of natural selection. (Prichard also recognized this in the second edition of his Researches Into the Physical History of Mankind.) Blyth also admitted that breeds "may possibly be sometimes formed by accidental isolation in a state of nature," something Lawrence had suggested might produce a race of "porcupine men." 112 However, neither Lawrence nor Prichard nor Blyth fully comprehended the creative role of natural selection which Darwin and Wallace later showed to be essential in the evolution of new species. In addition to Darwin, Wallace, and Blyth, a host of other major and minor figures in the development of the theory of evolution were familiar with Lawrence's book. In most cases, Lawrence's influence, if any, is difficult to determine. Many of these men developed no theories of their own, but were simply proponents of Darwinian evolution (Chambers is an exception). Nevertheless, it is worth mentioning them briefly to give some idea of how widely Lawrence's book was read by nineteenthcentury biologists. In the early editions of the Vestiges of the Natural History of Creation, Robert Chambers accounted for race formation in man in terms of environmental influences, but he also allowed for the possibility of the kind of spontaneous variation often observed in domesticated animals. In the following passage, in which the ancon sheep and porcupine men were cited as examples, Chambers gave Lawrence as his source. A notable instance of variety-production in an animal family by no means low, is often referred to, as having occurred under the observation of persons still alive to attest it. On a New England farm there originated, in the latter part of the last century, a variety of sheep with unusually short legs, which was kept up by breeding, on account of the convenience in that country of having sheep which are unable to jump over low fences . . . It appears only necessary, when a variety has been thus produced, that a union should take place between individuals similarly characterized, and that the conditions under which it has been produced should be persisted in, in order to establish it. Early in the last century, a man named Lambert, was bom in Suffolk, with semi-horny excrescences of about half an inch long, thickly growing all over his body. 112. Blyth (1835), in Eiseley, Proc. Amer. Phil. Soc., 103, p. 117.

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Sir William Lawrence The peculiarity was transmitted to his children . . . It was Mr. Lawrence's opinion, that a pair, in which both parties were so distinguished, might be the progenitors of a new variety of the race who would be thus marked in all future time.1t3 In the later editions of the Vestiges, Chambers omitted the material drawn from Lawrence and explained racial differences solely on a theory of racial progression toward the Caucasian type, coupled with environmental influences. In the twelfth edition (a reprint of the eleventh), Chambers said: On the whole, it results from inquiries into what is called the physical history of man, that conditions, such as climate and food, domestication, and perhaps an inward tendency to progress under tolerably favorable circumstances, are sufficient to account for all the outward peculiarities of form and color; so that these can only at the utmost serve as proofs of the distinctness of races, if supported by more decisive evidence.114 The reasons for this change are unknown, and it would require a detailed comparison of all the editions of the Vestiges to supply an adequate explanation. According to A. Hunter Dupree, Asa Gray, the most important American evolutionist, read Lawrence's book as a young man and was tremendously impressed by it. While there is apparently no firm evidence to suggest that Gray's acceptance of evolution was affected by his early reading of Lawrence, Dupree hints that Lawrence's view of man as a part of nature might have appealed to him. In any case, Gray expressed his admiration for Lawrence in a letter written in 1831, quoted by Dupree: That Lawrence is writer. I wish you a materialist-after to form an opinion

a grand fellow-a strong and agreeable to read whenever you can obtain it. He is my own fashion precisely-Don't attempt on such matters until you read it.115

Charles Lyell was also familiar with Lawrence's work, for a few references to it occur in his Principles of Geology.111 Yet 113. Robert Chambers, Vestiges of the Natural History of Creation, 2nd Amer. ed. (New York: Wiley & Putnam, 1845), pp. 196-197. 114. Robert Chambers, Vestiges of the Natural History of Creation, 12th ed. (Edinburgh: W. & R. Chambers, 1884), p. 339. 115. A. Hunter Dupree, Asa Gray (Cambridge, Mass.: Harvard University Press, 1959), p. 20. 116. Charles Lyell, Principles of Geology, 9th ed. (New York: D. Appleton & Co., 1856), p. 609.

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Lyell does not seem to have been influenced by the theoretical aspects of Lawrence's work as Blyth was; he quoted Lawrence only on factual matters. He accepted the inheritance of acquired characteristics and was not particularly aware of the importance of spontaneous variations. He also adopted the view that domesticated animals may have originally been endowed with a disposition to domestication in order to serve man, a type of natural theology alien to Lawrence.'17 Sir Joseph Dalton Hooker was apparently familiar with Lawrence's work, since he referred to the Lectures briefly in an address to the British Association in 1868. The citation is unimportant, however, and oddly enough is in reference to a few remarks Lawrence made on geology."18Thomas Huxley, on the other hand, was familiar with the anthropological contents of Lawrence's book and with the controversy which surrounded it. He seems to have known Lawrence personally, and at one time he presented Lawrence with a copy of one of his books.'"9 However, the following passage, from the 1894 preface to Man's Place in Nature, gives no hint of any influence which Lawrence might have had on Huxley. It was not so very long since my kind friend Sir William Lawrence, one of the ablest men whom I have known, had been well-nigh ostracized for his book 'On Man', which now might be read in a Sunday-school without surprising anybody.'20 Finally, William Bateson, who was so important in introducing Mendelian genetics into Great Britain, was quite familiar with Lawrence's ideas on genetics. He referred to Lawrence briefly in an article written in 1909,121 and again in a 1924 article, in which he said, Sir William Lawrence had (1818) collected many illustrations of variability, but maintains that none transgress the limits of specific differences, and he took a firm stand against the Lamarckian teaching of the transmission of acquired charac117. Ibid., pp. 591-600. 118. J. D. Hooker, "Address Before the British Association at Norwich," Every Saturday (Sept. 26, 1868), p. 393. 119. Leonard Huxley, ed. The Life and Letters of T. H. Huxley (New York: D. Appleton & Co., 1901), I, 305. 120. T. H. Huxley, Man's Place in Nature, 2nd ed. (New York: D. Appleton & Co., 1894), vii. 121. Beatrice Bateson, William Bateson, Naturalist (Cambridge (Eng.): Cambridge University Press, 1928), pp. 216, 220.

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Sir William Lawrence ters, which he declared was contrary to experience-the I believe, actively to denounce

first,

that illusion.122

It has now become clear that Lawrence's ideas on variation and heredity were not lost in the obscurity of time, but were discussed in scientific circles for a considerable number of years. The degree of his influence varied, but his Lectures were recalled again and again by leading biologists, from the groping, uncertain days of pre-Darwinian biology to the heyday of postMendelian genetics. THE DEVELOPMENT OF LAWRENCE'SIDEAS We have examined Lawrence's ideas on heredity and race formation as expressed in his Lectures of 1819, and we have seen the impact which they had on nineteenth-century biology. It will now be worthwhile to study the development of Lawrence's views as expressed in his earlier writings, and to attempt to determine the origins of his seemingly advanced ideas. This will in turn give us a clue to the way in which ideas which eventually fed into the work of Wallace, Blyth, and others developed and were transmitted. Early in his career, Lawrence showed an interest in problems of race formation. On October 4, 1803, at the age of twenty, Lawrence read a paper on the varieties of the human species to the Abernethian Society at St. Bartholomew's Hospital.123 Whether or not this paper still exists, I do not know. However, it was probably based largely on the writings of Johann Friedrich Blumenbach. In 1809, in Nicholson's British Encyclopedia, there appeared an article on "Man" written by Lawrence, in which he acknowledged that most of his information was taken from Blumenbach's De Generis Humani Varietate Nativa. There is no question that this article, which has not been noticed before, is by Lawrence, for in the preface to the Encyclopedia, Lawrence is cited as the author of articles on "Anatomy, Comparative Anatomy, the Natural History of Man, Physiology, Surgery, etc." 124 The article in Nicholson's Encyclopedia contained a discussion of the differences between man and animals which was similar to, but much shorter than the discussion in the 1819 Lectures. 122. Ibid., p. 402.

123. Norman Moore, The History of St. Bartholomew's Hospital (London: Pearson, 1918), II, 826-827. 124. William Nicholson, The British Encyclopedia, Amer. ed. (Philadelphia: Mitchell, Ames & White, 1821), I, vii. I have been unable to use the 1809 edition (listed in British Museum Catalog).

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Lawrence's views on heredity and race formation, however, as expressed in this article, were diametrically opposed to his later ideas. Lawrence's aim was the same as in his Lectures, to prove that man is of one species. The analogy with domesticated animals was used, undoubtedly due to the influence of Blumenbach, who popularized this approach to physical anthropology.125 Yet, in 1819 Lawrence emphatically denied that acquired characteristics could be inherited and dismissed climate, food, and way of life as unimportant in race formation. He took exactly the opposite point of view in this article. "Climate," he said, "has generally been regarded as the cause of national colour" and might also have "considerable influence on the hair." 128 Food and mode of life were also seen as important factors in race formation. Furthermore, the effects of these influences could be increased through breeding: The three causes now mentioned produce their effect in changing the original character of the animal, and giving origin to a variety, only after a great length of time, and a continued action through several generations. But these changes are communicated much more quickly by the process of generation. When two varieties copulate together, the offspring resembles neither parent wholly, but partakes of the form and other peculiarities of both.127 In addition, Lawrence stated that we have "many facts, shewing that, in some cases, casual mutilations are transmitted to the offspring; as want of tail in cat or dog." 128 There was no mention of spontaneous variation, no mention of the ancon sheep or porcupine men, no mention of sexual selection or geographical isolation. The treatment was almost pure Blumenbach, although Lawrence listed a number of additional sources, including Petrus Camper, Buffon, John Hunter's 'Disputatio Inauguralis de Hominum Varietatibus," Zimmerman's "Geographische Geschichte der Menschen," and Ludwig's "Grundriss der Naturgeschichte der Menschen-species." 129 Lawrence's early views on heredity were more fully expressed in several articles written for Abraham Rees's Cyclopedia. The publication dates of the various articles are difficult to determine, 125. Bendyshe, Anthropological Treatises of Blumenbach (see n. 15 above) passim. 126. William Lawrence, "Man," Nicholson's British Encyclopedia, VII, unpaginated. 127. Ibid. 128. Ibid. 129. Ibid.

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Sir William Lawrence since the volumes of the edition I have used are not dated. However, Collinson reports that publication of Rees's Cyclopedia was begun in 1802 and completed in 1820.130 The article "Cranium" is one of those written by Lawrence, for it is cited in his Lectures as having been written by him.131 It was evidently written at least as early as the 1809 article on "Man" in Nicholson's Encyclopedia where it is also cited.132 In "Cranium," Lawrence admitted that it is difficult to determine the causes of the varieties in the shapes of the human skull, but he offered Blumenbach's views on the subject for consideration. His whole treatment was essentially paraphrased from the third edition of Blumenbach's De Generis Humani Varietate Nativa (1795).133 He stated Blumenbach's idea that the skull could be modified by the facial muscles, which were in turn modified by climate. He also allowed for the possibility that artificial pressure might modify the shape of the skull and that the effects could be inherited. Like Blumenbach, Lawrence cited as an example the Macrocephali described by Hippocrates in Airs, Waters, Places. This was a nation of long-headed people who had supposedly lengthened the heads of their children for purposes of beautification. After several generations, the effects became hereditary. Still following Blumenbach, Lawrence described the pangenesis theory of Hippocrates and Buffon, which was often used to explain the inheritance of acquired characteristics: The father of medicine has endeavoured to explain this singular phenomenon by his hypothesis of generation, which is nearly similar to that of Buffon. He supposes the genital fluid to be collected from all parts of the body; and hence that the members of the foetus are fashioned according to those of the parents, from whom this fluid is derived; so that a Macrocephalous father would beget a son of the same formation, etc.134 Lawrence acknowledged that "some physiologists" denied that "tartificialforms of the cranium may ultimately be transmitted to 130. Robert Collinson, Encyclopedias: Their History Throughout the Ages (New York: Hafner, 1966), p. 109. 131. Lawrence, Lectures, p. 332. 132. Lawrence, "Man," Nicholson's British Encyclopedia, VII, unpaginated. 133. Bendyshe, Anthropological Treatises of Blumenbach, pp. 203-204. 134. William Lawrence, "Cranium," The Cyclopedia; or Universal Dictionary of Arts, Sciences, and Literature, ed. Abraham Rees (Philadelphia: S. F. Bradford, n.d.), X, unpaginated. Lawrence does not use the term "pangenesis," which was introduced by Charles Darwin in 1868.

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the offspring," and he admitted that there was too little evidence to "determine the question satisfactorily on either issue." However, he wrote: The transmission of other national marks, as peculiar forms of the features, and of organic diseases, as defects of pronunciation, not to mention various instances in which casual mutilations have passed to the offspring, will induce us to reflect a little before we adopt implicitly the negative side of the question.'35 This passage, like all the others, was taken almost directly from Blumenbach.136 In fact, there was very little in the article that was original with Lawrence. His later ideas notwithstanding, Lawrence was at this time apparently willing to follow Blumenbach in accepting the inheritance of acquired characteristics and the pangenesis theory of Buffon. However, in a later article on "Generation," in Volume XVI of Rees's Cyclopedia, Lawrence rejected Buffon's pangenesis theory as "vague chimeras" which were "destitute of foundation" and hardly "worthy of notice." 137 He gave a brief summary of Buffon's theory, which held that particles in the body were shaped by an "interior mould" and then carried to the genital organs where they were stored. These particles enabled parents to produce offspring like themselves.138 The reasons for Lawrence's rejection of Buffon's pangenesis at this point are unclear, especially since the exact date of the article is unknown. However, in "Generation," Lawrence was more concerned with theories of sexual reproduction than with problems of heredity. Therefore, although he rejected Buffon's pangenesis, he did not directly address the problem of the inheritance of acquired characteristics. In the article on "Man" in Rees's Cyclopedia, Lawrence expressed views which are essentially the same as those found in his 1819 Lectures, and it seems likely that the article was written at approximately the same time. In fact, much of the wording of the article was identical with that of the Lectures. In any case, Lawrence's views on heredity as expressed in this article were completely different from those in the Nicholson's Encyclopedia article and in "Cranium." The inheritance of acquired 135. Ibid. 136. Bendyshe, Anthropological Treatises of Blumenbach, pp. 203-204. 137. William Lawrence, "Generation," Rees's Cyclopedia, XVI, unpaginated. See Lawrence, Lectures, p. 367 for reference to "Generation" as having been written by Lawrence. 138. Lawrence, "Generation," Rees's Cyclopedia, XVI.

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Sir Willam Lawrence characteristics was emphatically denied, and the varieties of man were explained in terms of transmission of spontaneous variations. The examples of the ancon sheep and porcupine men were discussed, and the role of breeding and sexual selection in man were described.'39 What caused Lawrence to alter his views on the nature of heredity so dramatically? The answer lies in the expanded list of sources which Lawrence cited in the Rees Cyclopedia article on "Man" and in his Lectures. A number of sources were added to those listed in the Nicholson's Encyclopedia article, but one was given particular emphasis. This source was James Cowles Prichard, of whom Lawrence said, "[His] clear statements, convincing reasoning, and very extensive information, stamp the highest value on his interesting work, and distinguish it very advantageously from most other productions on the same subject." 140 Prichard's major work was published in a number of editions, first appearing as Disputatio Inauguralis de Generis Humani Varietate (1808).'41 In 1813, it was expanded and translated as Researches Into the Physical History of Man. A two-volume second edition, quite different from the first, appeared in 1826. A third edition of five volumes was begun in 1837, and this was later reprinted as the "fourth edition" several times. This fivevolume edition was again much altered. Prichard was heavily influenced by Blumenbach, as was Lawrence, and both men dedicated their books to Blumenbach. Prichard used the domesticated animal analogy to prove the unity of the human species. Yet he diverged from Blumenbach in denying the inheritance of acquired characteristics. "The offspring," he said, "inherit only their connate peculiarities and not any of the acquired qualities." 142 He ascribed race formation in man to the propagation of "connate" varieties, just as Lawrence did. He used the examples of the ancon sheep and porcupine men, and it seems likely that Lawrence first read of these varieties in Prichard. Indeed, a close examination of the first edition of Prichard's Researches reveals that virtually all of the major elements of Lawrence's 1819 treatment are present, and there is no doubt that Prichard was Lawrence's major source. Prichard fully 139. William Lawrence, "Man," Rees's Cyclopedia, XXIII, unpaginated. 140. Lawrence, Lectures, p. 113. 141. James Cowles Prichard, Disputatio Inauguralis de Generis Humani Varietate (Edinburgh; Abernethy and Walker, 1808). 142. James Cowles Prichard, Researches Into the Physical History of Man, 1st ed. (London: J. & A. Arch, 1813), p. 230. See n. 92 above for bibliographical information on other editions of Prichard's work.

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recognized the role of selection in the breeding of animals and applied it to man: If the same constraint were exercised over men, which produce such remarkable effects among the brute kinds, there is no doubt that its influence would be as great. But no despot has ever thought of amusing himself in this manner, or least such an experiment has never been carried on upon that extensive a scale, which might lead to important results.143 Prichard also recognized the analogy between artificial selection in domesticated animals and sexual selection in man, and he actually stated it more clearly than Lawrence: The perception of beauty is the chief principle in every country which directs men in their marriages. It does not appear that the inferior tribes of animals have anything analogous to this feeling . . . This peculiarity in the constitution of man, must have considerable effects on the physical principle of improvement, supplying the place in our own kind the beneficial control which we exercise over the brute creation.144 Prichard himself has been as misunderstood as Lawrence. E. B. Poulton read the second edition of the Researches and found "a remarkable anticipation of modem views on evolution."'145 Darlington lumps Prichard with Lawrence as one of the English "medical evolutionists." 146 Conway Zirkle states that Prichard had a "very accurate idea of evolution."147 It is true that, like Lawrence, Prichard anticipated important elements of Darwinian evolution: spontaneous variation, sexual selection, geographical isolation, etc. In the 1826 edition of his work, he went much farther than Lawrence and recognized the conservative aspect of natural selection.'48 He also discussed 143. Ibid., p. 40. 144. Ibid., p. 41. Prichard probably derived his ideas on sexual selection from Samuel Stanhope Smith, whom he cites (p. 41). Lawrence also drew on Smith's views (see n. 26 above). 145. E. B. Poulton, "A Remarkable Anticipation of Modern Views on Evolution," in Essays on Evolution (Oxford: Clarendon Press, 1908), pp. 173-192. 146. Darlington, Darwin's Place, pp. 16-18. 147. Conway Zirkle, "The Early History of the Idea of Acquired Characteristics and of Pangenesis," Trans. Amer. Phil. Soc., n.s. 35 (1946), 117. 148. Prichard, Researches (1826), II, 557-581. It should be noted that Prichard's views changed drastically in each edition of his Researches. In the third edition (1836-1847), he was willing to allow for the inheritance of acquired characteristics (see n. 92 above for bibliographical details). In his Natural History of Man (4th ed., London: H. Bailliere,

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Sir William Lawrence the geographical distribution of animals at great length and was frequently quoted by Lyell in the Principles of Geology on this subject.149 However, Prichard consistently supported the concept of fixed species, just as Lawrence did. In a book published in 1829, in one of his few direct references to evolution, Prichard specifically refuted the evolutionary doctrines of Geoffroy St. Hilaire and Erasmus Darwin.'50 Nevertheless, Prichard's views on heredity and variation, as expressed in the 1813 edition of his Researches, were certainly advanced for his time, although their origin is unclear and would be an appropriate subject for another whole paper. What obviously impressed Lawrence, however, was Prichard's ability to distinguish between spontaneous and acquired variations, something on which Blumenbach had been vague. Blumenbach, in fact, believed that "peculiarities which happen accidentally to one or two individuals" were of little importance in race formation, and that only "varieties of whole nations" should be considered.151 This explained the fact that albinos did not form a distinct race. Prichard, on the other hand, said, "We see no instance of connate variety, however trifling, which does not manifest a tendency to become hereditary and permanent in the race," and he specifically cited albinos as an example.152 The shift from a consideration of variations in whole races to a discussion of variations in individuals was the most important element of Prichard's work, and it became the most important of Lawrence's as well. By denying the inheritance of acquired characteristics as Prichard initially did, he and Lawrence were able to show that only individual variations could be the source of new breeds or races. The origin of these variations must be spontaneous, since external factors would be unlikely to work only on one individual. The ancon sheep and porcupine men provided concrete proof that such variations did occur de novo, and that they were hereditary. Lawrence's emphasis on individual variation led Wallace to realize very early that species might 1855), he seems to have completely accepted the inheritance of acquired characteristics (I, 24-70). The reasons for this change of view are not entirely clear, but it is important to determine which editions of his works were read by later naturalists, if an accurate picture of his influence is to be obtained. Lawrence could not have read the second (1826) or third (1836-1847) edition prior to the publication of his Lectures in 1819, so I have limited my discussion to the first (1813) edition. 149. Lyell, Principles, pp. 615, 630-635, 643, 647. 150. James Cowles Prichard, A Review of the Doctrine of a Vital Principle (London: Sherwood, Gilbert and Piper, 1829), p. 227. 151. Bendyshe, Anthropological Treatises of Blumenbach, p. 129. 152. Prichard, Researches (1813), p. 25.

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be produced from "certain distinctive peculiarities in some Individuals."153 It also enabled Blyth to adopt his classification of varieties, in which he distinguished between the spontaneous "'simple"and "true" varieties, and acquired variations. The emphasis on individual variation also led Wallace and Blyth to recognize the importance of selection in perpetuating new varieties. In the case of Wallace, it was natural selection that was found to be important. Blyth, on the other hand, recognized the importance of artificial selection in maintaining new breeds, but failed to grasp the creative aspect of natural selection. Even allowing for the fact that neither Lawrence nor Prichard was truly an evolutionist, there still is a danger of reading too much modernity into their ideas on heredity. Since actual knowledge of the mechanisms of inheritance was nonexistent at this time, Lawrence and Prichard were at a loss to explain the causes of what I have referred to throughout this paper as spontaneous variations. They actually called such variations "de novo," "connate," "congenital," or "accidental," terms which Prichard admitted were "only expressive of our ignorance as to the causes which give rise to them." 154 Lawrence also professed ignorance of the causes of variation.155 Nevertheless, both men suggested that the artificial conditions of domestication might have some influence on the reproductive system.'56 Prichard never really spelled out his conception of how the reproductive system might be affected, nor did Lawrence in his Lectures. However, in an article entitled "Monster" in Rees's Cyclopedia, Lawrence discussed possible causes of monstrous births. He seems to have conceived of the major cause as some sort of disruption of foetal. development, although he was necessarily rather vague on the subject. We now know that such embryological birth defects cannot be inherited, but Lawrence had no way of knowing that. Thus, he wrote, Observation . . . exhibits to us the production and development of the foetus as the result of vascular action in secretion and nutrition . . . The function of generation is not more exempt from the operation of disturbing causes than any other in the animal economy. Any violent and sudden impression interrupts it at once by causing abortion; but minor causes, although their effects are not seen, are not to be deemed inop153. McKinney, "Wallace's First Observations" (n. 83 above), p. 372. 154. Prichard, Researches (1826), II, 548. 155. Lawrence, Lectures, p. 438. 156. Prichard, Researches (1813), pp. 207-228; Researches (1826), II, 580; Lawrence, Lectures, pp. 383-384, 438.

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Sir Wfiliam Lawrence erative. Particular bodily formations, particular mental characters, and dispositions to certain diseases, etc., etc., are transmitted to the offspring . . . We ascribe then the aberrations from the usual form and structure of the body, which produce monsters, to an irregular operation of the powers concerned in generation.157 It is clear, then, that despite the modern sound of Lawrence's ideas on heredity, he was as ignorant of the actual mechanism of inheritance as were his contemporaries. It is to the credit of Lawrence and Prichard that they were able to conclude from the evidence available to them that acquired characteristics could not be inherited and that spontaneous variations did occur. However, to say that they "took up the challenge of Lamarck," as Darlington does, is to misinterpret their aims.'58 They were in no way concerned with finding a new source of variation in evolution, to oppose Lamarck's theories, and Lamarck himself was almost never mentioned by either of them. Their concern was simply to explain the formation of human races. That in the course of this explanation they hit upon an essentially modern concept of heredity and variation, is largely incidental. What is particularly interesting about Lawrence is that he was basically an armchair biologist who based his Lectures primarily on previously published material. Having adopted Blumenbach's domesticated animal analogy as his basic starting point, Lawrence was converted to the theory of race formation by spontaneous variation through his reading of the first edition of Prichard's Researches. Having adopted this theory, all that remained was for Lawrence to buttress his arguments with numerous examples drawn from a wide variety of literature on travel, ethnology, stock breeding, anatomy, and physiology. If Lawrence's work was more influential than Prichard's, as seems to have been the case, it may have been partly due to Lawrence's clearer, more precise style of writing. Prichard tended to ramble, filling volumes with ethnological details. In addition, Lawrence's book remained unchanged and in print for almost fifty years (the last printing was in 1866).159 Prichard, on the 157. William Lawrence, "Monster," Rees's Cyclopedia, XXV, unpaginated. The fact that Lawrence wrote the article has been established through cross references to other articles he wrote and a comparison of the text with his Lectures. 158. Darlington, Darwin's Place, p. 16. 159. I have seen copies of, or reference to, the following editions of Lawrence's Lectures: 1819 (London: J. Callow); 1822 (London: W. Benbow); 1822 (London: Kaygill & Price);; 1823 (London: J. & C. Smith); 1823

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other hand, was constantly revising his Researches, thus leaving the early editions outdated and out of print. For this reason, many of the evolutionists may have read only the third edition, in which many of his most interesting ideas were either obscured or omitted (Darwin, for example, read only the third edition).160 What makes Lawrence's influence on someone like Wallace so remarkable, and at the same time, paradoxical, is the fact that he was not an evolutionist. Furthermore, his book contained very little that was original. The first of these paradoxes is due largely to the fact that Lawrence was a man with an eighteenthcentury background whose influence was felt in the nineteenth-century. Most of his sources were eighteenth-century authors, with the exception of Prichard, who was himself a product of the eighteenth-century. Hence, Lawrence adopted the accepted view of fixed species in nature. Since he was concerned with the extent of variation within a single species, human or animal, there was no reason for him to alter his views in this respect. Wallace, on the other hand, having previously read the Vestiges of Creation, was already convinced of the truth of evolution when he read Lawrence's book. Thus, the same sort of hindsight which has led modem authors to call Lawrence an evolutionist led Wallace to consider Lawrence's ideas from an evolutionary point of view. As McKinney has remarked, there never was a "species barrier" for Wallace.116 He therefore immediately realized that Lawrence's permanent varieties might just as well be called species. With respect to the problem of Lawrence's lack of originality, we should remember that even Darwin's great work had two distinct components. On the one hand, there was his original theory of natural selection. On the other hand, there was his immense compilation of previously recorded facts drawn from a vast array of source materials. Lawrence developed no original theory of his own, although he adopted and clarified Prichard's ideas. His Lectures were important primarily because they collected in a clear and logical manner useful information which had been available previously, but only in widely scattered sources. Lawrence played the role of the encyclopedist, a compiler of ideas as well as facts. His work thus served as a sort of pipeline through which important concepts of heredity and (London: R. Carlile); 1828 (Salem, Mass.: Foote publisher unknown); 1844 (London: J. Taylor); 1866 (London: Bell & Daldy). 160. Smith, "Origin of the 'Origin'" (n. 67 161. McKinney, "Alfred Russel Wallace," p.

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and Brown); 1840 (London: 1848 (London: H. G. Bohn); above), p. 399. 87.

Sir William Lawrence variation were able to feed directly into the mainstream of evolutionary theory. Acknowledgments I would like to express my appreciation to Professor Seymour H. Mauskopf of the History Department, Duke University, and Professor William B. Provine of the History Department, Cornell University, for their valuable suggestions and comments on this paper. I would also like to thank Professor Donald Ginter, History Department, Duke University, for first introducing me to rigorous historical research.

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Fontenelleand the Problemof Generation in the EighteenthCentury ALAIN F. CORCOS Michigan State University East Lansing, Michigan

"L'autorite a cesse d'avoir plus de poids que la raison." Preface de l'Histoire de l'Acade6mie des Sciences depuis 1666.

Bernard Le Bovier de Fontenelle (1657-1757) was considered by French literary critics a witty, elegant writer, an influential philosopher, and an excellent popularizer of science. His reputation is based primarily on works that were published before 1700.1 Among his later works, Eloges des Academiciens has been highly praised. However, the importance of his Histoire de l'Academie Royale des Sciences.2 seems to have been ignored or very little written about, and yet it might be the most important source for us to find out about Fontenelle's scientific ideas. Fontenelle, under the influence of his two uncles, Pierre and Thomas Corneille, tried his hand at writing, but failed as a poet and dramatist. He then turned to science, and his main contribution before 1700 was to popularize the scientific achievements of the seventeenth century. In his famous dialogue, entitled "The Plurality of Worlds," he made the discoveries of physical science clear, intelligible, and amusing to the general public. In many respects this book could stand as a model for modem scientific popularization. However, Fontenelle did not merely popularize the scientific 1. Bernard de Fontenelle's most important philosophical works are Dialogue des Morts, 1683; Entretiens SUT la pluraliM des Mondes, 1686; Histoire des Oracles, 1687; Digression sur les Anciens et les Modernes, 1688. 2. Histoire de l'Academie Royale des Sciences, 1699-1740, 42 vols. The Histoire and M6moires for each year were printed in the same volume with separate pagination. Fontenelle is the author of these volumes throughout this period. Several volumes passed through more than one edition, and consequently the pagination may differ in different sets. The one I used is the original edition of 1702, edited by Jean Boudot. Journal of the History of Biology, vol. 4, no. 2 (Fall 1971), pp. 363-372.

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achievement of the seventeenth century. He also played a large role as an historian of science in his position as Perpetual Secretary of the French Royal Academy of Sciences where he served from 1697 to 1740. As one of his duties he wrote each year the history of the Academy, and this involved reading all the "Memoirs" submitted during the year, assessing their importance, and writing an abstract of their conclusions. Fontenelle did this with a skill that has never been surpassed. Did he always understand the discoveries which under his pen seemed so simple? Had he mastered the various theories which he discussed with such ease? When one reads his writings on the one hand and the Memoirs on the other, one has to admit that Fontenelle indeed appears to have understood most of the scientific problems, especially the biological ones. He seemingly could grasp the more complex hypotheses, follow their deductions to their ultimate conclusions, and in many cases transcend the report itself and develop ideas of far-reaching importance. This seems to have been especially true in the field of reproduction. Though, at that time, many concrete and correct anatomical observations had been made, the true nature of reproduction was still in the domain of speculation. In the first half of the seventeenth century belief in spontaneous generation was widespread. Such a belief was compatible with the idea of the total mechanism of Descartes, for whom the laws of motion could produce living things at any time, just as they had produced them in the beginning. However, at the end of that century, many scientists3 could not conceive that a fly, a fungus, a worm, or even a microorganism whose existence had just been revealed by the work of Leeuwenhoek, could be generated from a medium deprived of life. The outstanding feature of life is the continuous creation of an extremely high degree of orderliness. A fly or a fungus is highly ordered and therefore a most improbable structure. This means that these oragnisms are most unlikely to be spontaneously generated from particles united at random, no matter how "fermented" is the medium.4 Little by little, 3. N. Andy, De la generation des vers dans le corps de l'homme (Paris, 1700); G. Baglivi, "Lettre a Andy," in De la g6n6ration des vers, p. 429; J. B. Duhamel, De consensus veteris et novae philosophiae libri duo (Paris, 1663). 4. This concept, which seems highly modern, was expressed as early as 1700 by Andy (see n. 3 above), who would accept the belief in spontaneous generation if it could be explained to him "comment le d6sordre du hazard peut arranger avec tant d'ordre les parties organiques d'un animal." Fontenelle, in 1724, in his short essay, "De l'existence de Dieu," expressed the same idea. See Oeuvres V (Paris; Bastien-Servieres, 1790),

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Fontenelle and the Problem of Generation examples which had been cited in favor of spontaneous generation were shown to be invalid. Redi's experiments indicated that worms did not come from putrefaction but from eggs that flies had laid. At the end of the seventeenth century the work of Malpighi, Swammerdam, Leeuwenhoek, Lister, and others on the metamorphosis of insects, gall formation in plants, and the study of sexual organs and mating in animals led to the theories of preformation and pre-existence of germs. The distinction between those two theories had not been clear even among their proponents. Both theories affirm that the organism does not form from homogeneous matter, but from a germ in which the organism is simply the growth of its parts. Some proponents of the theory of pre-existence believed that the germ was created by God at the beginning of the world and had been kept that way until its growth, the adult organism being only the shelter and the food purveyor of its offspring. Among those who strongly denied the idea of spontaneous generation was Fontenelle. To attack the idea he used a report by Tournefort on the cultivation of mushrooms.5 The report begins: "The way mushrooms are cultivated favors the idea of those who believe that mushrooms sprout from seeds the same way other plants do." Toumefort then describes the development of mushrooms from hyphae and the formation of the cup with its laminae. Although he was not able to see any of the seeds, he was sure they were produced by mushrooms and fell in the horse manure which was used as a hot seedbed. To him the horse manure was just a source of heat and not a medium from which the mushrooms spontaneously sprouted. Here is a translation of Fontenelle's comments on Tournefort's report.6 Modern scientists either with the help of the microscope or by a certain exactitude in their research have discovered seeds from several plants, for example the ferns, which were believed until then not to produce any. These seeds are either 321-330; "Les animaux ne se pepertuent que par la voie de la g6n6ration, mais il faut n6cessairement que les deux premiers de chaque espece aient ete produits ou par la rencontre fortuite des parties de la matiere, ou par la volont6 d'un etre intelligent qui dispose de la matiere selon ses desseins." To Fontenelle "parties de la mati6re" are atoms, for he adds, "Ces atomes circulent sans cesse: ils forment tantot une plante, tantot un animal; et apres avoir form6 l'un, ils ne sont pas propres a former l'autre. Ce ne sont pas les atomes d'une nature particuliere qui produisent les animaux: Ce n'est qu'une matiere indifferente dont toutes choses se forment successivement." 5. MWm. Acad. Sci. (1707), p. 58. 6. Hist. Acad. Sci. (1707), p. 46.

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so small or so extraordinarily located that one either is unable to see them with the naked eye or may mistake them for something else. As far as mushrooms and some other plants are concerned, we have still not progressed any farther than the Ancients. No matter how industrious one is in looking for these seeds in different and far-off places, one still cannot find any. The cultivation of mushrooms seems to confirm that they have no seeds. Mr. Tournefort made a detailed, very instructive study, and thereby has increased our interest in the origin of mushrooms. In general, they sprout from horse manure. However, what is the relationship between horse manure and mushrooms? What ability has it to produce them? One could believe as the ancients did that an ox produces bees, or that the spinal cord of a dead man exposed in the hot sun for a long time changes into a snake. Such unreasonable metamorphoses are not more unreasonable than that of horse manure to mushrooms. But one has to go back to certain rigorous philosophical principles which will set limits to too uncertain speculations. When one considers the structure of a plant, how beautifully and delicately constructed, it is inconceivable that this haphazard mixture of saps can on the one hand be so regular as to always produce the same plant, and on the other hand so limited in scope that it never produces a new plant. Furthermore, as soon as one sees the smallest part of the newborn plant, that plant is already completely formed and it is reasonable to assume that it does nothing after its birth but grow into a mature plant. Otherwise we have to assume that merely looking at the birth of a plant is responsible for suddenly changing the way Nature operates. Because of the comparatively great number of plants which produce and grow from seeds, we can put forth the idea that the plants which seem to lack seeds have some. If the Ancients had been more careful in their observations and deductions, they would not have believed that plants without seeds existed. We would be less excusable if we believed as they did, since for us the number of plants which have no visible seeds is smaller. We can assume without fear of contradiction that all plants have seeds and be sure that experience will bear us out. But it is certain that seeds do not germinate everywhere. They must find certain saps which are able to penetrate their envelopes, to cause a fermentation, the first process of de-

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Fontenelle and the Problem of Generation velopment in the small plant, and to join those small parts in order to increase their number. Here lies the infinite diversity of places in which are born the different plants. What Mr. Tourenfort has learnt from Mr. Mery and Mr. Lemery is even more surprising. There is a kind of mushroom that grows on bandages and casts applied to the broken limbs of the sick in the hospital (Hotel Dieu). No wonder that horse manure prepared as Mr. Tournefort has reported is a special kind of earth or matrix capable of germinating ordinary mushroomsl It can then be deduced from this that mushroom seeds must exist in large quantities in an infinity of places where they do not germinate, possibly all around the earth. This must also be true for the invisible seeds of many other plants. It must be said that our imagination rebels against this prodigious number of seeds seeded everywhere, so useless in many places. However, we have to accept this idea. For without it, we cannot explain the appearance of swamp plants in newly formed swamps which did not contain those plants previously. We cannot explain the appearance of black peonies in the burned acreage in Languedoc, Provence, in the islands of the Archipelago, and the fact that in years following the London fire a great quantity of Erysimum latifolium maius glabrum appeared. These facts and many others which we could bring forth prove the multiplicity of seeds and the necessity of certain circumstances to make them germinate. This idea is all the more reasonable-first, since the plants which we believed had no seeds have the most; second, because these seeds can be easily carried to an infinity of places by chance alone; and third, because they are better protected by their small size from adverse conditions and are not affected by change for a long time. We can say they are more particular in the choice of saps and other factors which enable them to develop. If we speculate in the same manner on the invisible eggs of insects, the earth will be full of an incredible infinity of plants and animals already perfectly formed, though in a small scale, and waiting only for a favorable accident to grow. One can imagine though very imperfectly how rich is the Hand which has seeded them with so much profusion. The idea that mushrooms must spread their invisible seeds in many places was already in Tournefort's mind as early as 1692,7 7. Hist. Acad. Sci. depuis 1666 jusqu'd son renouvellement (Paris: Martin & Coignard, 1733), 153.

en 1699, II

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for he had communicated to the Royal Academy his thoughts on the development of a mushroom which was found growing on the main beam of a church in Paris. He then asked the rhetorical question: Did such a mushroom originate from a seed which by chance had sprouted on the medium where it was found? In 1701, Fontenelle had already affirmed that all plants came from eggs for "the seeds are eggs under another name."8 If plants do not generate spontaneously, do animals do it? Fontenelle denied this, even in the case of small animals. According to Fontenelle,9 a friend of Academy member Carre was led by the results of Redi's experiments to believe that the microscopic animals readily found in water came from the eggs of invisible flies. However, the results of the following experiment led him to discard that idea. This man'0 boiled a mixture of water and manure, with which he filled two bottles. When these bottles were half warm, he put two drops of water containing microscopic animals in one of them. Eight days later he found this bottle full of the same kind of animals that he had previously observed in the two drops of water. In the other bottle, however, nothing appeared, although the manure should have produced animals, according to the proponents of the doctrine of spontaneous generation. Fontenelle, commenting on this experiment, concluded that microscopic animals reproduce in water. He did not know how they reproduce, but added with tongue in cheek (see footnote above): That small animals multiply in the water is well established. However, this fact would have been better established if the philosopher had seen these animals mate. It is true that he saw them unite two by two. One might believe that it was to fight, but why should they fight only two by two. The microscope already widely used at the time of Fontenelle had revealed that microscopic life was highly organized. Such a complex organization could not result from such a random process as demanded by spontaneous generation. Fontenelle had himself expressed this idea when he made comments on a "memoire" of Claude Perrault in 1679 :11 "We are at at loss to understand how a liquid of any kind, and a fermentation of any conceivable type, might give rise to an organized body in which 8. Hist. Acad. Sci. (1701), p. 38. 9. Ibid., (1707), p. 8. 10. The name of the friend of Mr. Carre is not known by the writer. Fontenelle referred to his as "the famous friend of Mr. Carre." 11. Hist. Acad. Sci. depuis 1666 jusqu'd son renouvellement en 1699, 1, 279.

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Fontenelle and the Problem of Generation such a prodigious number of different parts have to be arranged in so many unique ways." He emphatically repeated his ideas about spontaneous generation in 1724, in a curious little book, "On the Existence of God."12 All the animals which seemed to sprout from rotten, wet and heated material are really developed from seeds or germs that cannot be seen. Never were worms generated from meat where no flies were able to deposit their eggs. And this is true of any animal believed to be spontaneously generated. To believe in spontaneous generation is an error that every modern experiment tends to refute. Fontenelle is sure that in the near future no doubt will remain on this subject. This gives him an argument in favor of the existence of God. The earth was the same in the past as it is now, and to-day no matter can just by chance reconstruct living things, this impossibilty was no less in the past. One cannot prevent oneself from attributing to a Creator the birth of the first living things. If Fontenelle did not believe in spontaneous generation, how did he explain the process of reproduction? He believed, as many members of the Academy of that time did, that any organismincluding man-originates from an egg.13 This belief in the case of mammals was based on analogy with oviparous animals. If birds and reptiles grow from eggs, why should there not be something similar from which a man or woman might grow? The search for a human egg had been intensive and difficult, a source sometimes of bitter disappointment, sometimes of high hopes. It ended in 1827 when von Baer discovered it in the Graafian follicle. At the time of Fontenelle, however, some scientists thought they had seen it, but their findings were contradicted by others. What they saw is believed now to have been Graafian follicles, cysts, or developing embryos. One source of confusion was that many anatomists were looking for an egg more or less similar to a bird egg. On this point Fontenelle seems to have been as confused as his contemporaries. He wrote in1701:14

One wants eggs, and one finds in the ovaries only small cells full of liquid that can never be thought of as an egg. No 12. Bernard de Fontenelle, Oeuvres V (Paris: Bastien-Servieres, 321-330. 13. Hist. Acad. Sci. (1701), p. 38. 14. Ibid., (1701), p. 39.

1790),

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membrane can be seen around the pretended eggs. Furthermore, those eggs must go out of the ovary and the common membrane which wraps the ovary is so tight, that it is inconceivable that a round and flabby egg can penetrate it. Though the egg remained invisible, the "ovism theory" which maintained that the adult animal was already formed in the egg was still dominant. Possibly it remained dominant because no one had proposed a better theory. Fontenelle, nevertheless, had some reservations about the ovism theory because it could not explain the regeneration of mutilated parts of the crayfish and other animals. Regeneration was largely ignored by the biologists of that time, possibly because it contradicted any theory of preformation. However, Reaumur had in 171215 documented the observation, well known among fishermen, that if a leg of a crayfish is cut, another one identical to the first will grow out. Fontenelle, commenting on Reaumur's report, wrote the following: The theory of ovism that maintains that the animal is already formed in the egg explains rather well the phenomenon of generation which is rather marvelous. But that a part of an organ similar to the one which has been cut from an animal is reborn, that is a second marvel of a different nature from the first one, and that cannot be explained by the theory of ovism. Fontenelle seems to have been more skeptical than Reaumur, who attempted to explain the phenomenon of regeneration of parts by postulating preexisting germs of legs. Unfortunately, Fontenelle did not suggest any other hypothesis to explain Reaumur's observations. Yet regeneration of parts was definitely an obstacle to the theory of preformation, an idea which was developed ten years later by Hartsoeker.16 Fontenelle was sometimes skeptical, sometimes evasive, sometimes both, but his skepticism was an asset in his reporting when so many unfounded stories were still in the minds of his contemporaries. His skepticism was apparent when he discussed the ideas of "monsters." For many years reports were made to the Academy on the birth of children missing some essential part or having such in excess. Two explanations had been presented: one that the monsters were the result of some accident to the egg, the 15. Ibid., (1712), p. 35. 16. Nicolas Hartsoeker, Recueil de plusieurs pieces de physique (Utrecht, 1722).

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Fontenelle and the Problem of Generation other that the eggs themselves already contained monsters, just as other eggs contained normal individuals. To Fontenelle17 the existence of monsters could not be attributed to accidents of nature. Nature does not play games; it always follows the same rules. Its works may be extraordinary but never irregular. So Fontenelle looked for the cause of monsters in Nature's laws, where chance does not play a role. His position on this matter was personal. Most of the philosophers of his time either attributed the existence of monsters to chance or to God. At first Fontenelle, with some hesitation, attributed the formation of monsters to the attachment of two eggs, the extra parts being those of the second egg with some of the parts missing.18 By 171219 he had become increasingly reluctant to report any more stories of monsters because they did not lead to any rational explanation. In 1724,20 his skepticism reached its highest point. He compared the idea of formation of a monster by the attachment of two eggs to that of two good clocks, broken after a sudden shock against each other, forming a third one with a perfectly regulated mechanism. In conclusion, Fontenelle's ideas on reproduction are clear. He denied the idea of spontaneous generation on the grounds that an organism is highly ordered, and in consequence unlikely to be spontaneously generated from particles united at random. Instead, he believed every organism came from a preexisting organism via a germ or a seed. He was led to believe the theory of "ovism," which claimed that the egg contained the organism folded together as a flower in a bud or as a chicken embryo in an egg. Later he had reservations concerning this theory and expressed them forcefully. Yet, he never proposed another theory, never mentioning, for example, a possible role for the spermatoza, which had been discovered as early as 1677. Nor did he ask why, if the fetus were merely the exfoliation of a seed that comes from the mother, do children resemble their fathers?2' Fontenelle's role in science has been neglected, perhaps because he was never a "practicing scientist." He never carried out an experiment. Many French writers have denied him his 17. Hist. Acad. Sci. (1703), p. 28. 18. Ibid., (1712), p. 48. 19. Ibid., (1712), p. 39. 20. Ibid., (1724), p. 20. 21. In 1759, Maupertuis became the first scientist to raise this important question in his book, The Earthly Venus. An English translation of this book has been made by Simone Brangier Boas (New York, Johnson Reprint Corporation, 1966).

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talents. Bertrand,22 for example, went so far as to say that Fontenelle was superficial, a dilettante; that he lacked critical sense and could not judge theories on their merits. Nevertheless, if we follow Fontenelle's ideas on a single subject, such as reproduction, we have to admit that he knew how to judge ideas, and that when he had to choose between theories, he generally chose the most logical one. In his Histoire de l'Academie one can find numerous personal ideas which indicate how much Fontenelle had thought about the many aspects of science, and their interaction, and yet this multivolume work as a source of eighteenth-century scientific ideas has been largely ignored by subsequent historians of science.23 22. Bertrand, L'Acad6mie des Sciences et les Academiciens (Paris: Hetzel, 1869), pp. 207-212). 23. Jean Rostand, in his book Biologie et Humanisme (Paris: Galimard, 1964), has given credit to Fontenelle for being a man of science as well as a man of letters. He deplores that his Histoire de l'Academie is not read by anyone.

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Hanson, Norwood Russell. Perception and Discovery. An Introduction to Scientific Inquiry. Edited by W. C. Humphreys. San Francisco, Cal.: Freeman, Cooper, and Co., 1969. x+ 435 pp.; $9.75. One of N. R. Hanson's unfinished projects at the time of his death in a plane crash in April, 1967, was an introductory textbook in the philosophy of science, drawn from his lectures at Yale, Indiana University, and Cambridge. This volume has been constructed by W. C. Humphreys from the materials Hanson was working on, intended as an introductory text for college-level science students. At the same time, as those familiar with Hanson's other writings could anticipate, the book has enough depth and richness to appeal to the working philosopher, scientist, or historian of science. Hanson's emphasis is on the roles of observation and experimentation in theoretical science, and he draws heavily upon historical events to exemplify his analysis. His fundamental approach in describing and analyzing the nature of science is the Wittgensteinian, ordinary language theory of perception. Joravsky, David. The Lysenko Affair. Cambridge, Mass.: Harvard University Press, 1970. xiii + 459 pp.; $13.95. From 1929 to 1964, Soviet agriculture and many of its scientific endeavors were dominated by the "agrobiological" policies of T. D. Lysenko. David Joravsky, Professor of History at Northwestern University, has spent several years collecting and analyzing available documents on the "Lysenko affair," using them to examine the nature of Soviet state management in terms of the interactions between agriculture, natural science, MarxistLeninist ideology, and political power. On the basis of his study and interpretation of Lysenko's rise and fall, Joravsky disputes a common Western interpretation of the Lysenko affair. Genetics, he holds, was not denounced by the Soviet regime under Lysenko's sway because it threatened the Marxist ideology. Rather, Joravsky believes, "the historical reality was far less high-minded and far more serious. Lysenko's school . . . rebelled against science altogether.

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Farming was the basic problem, not theoretical ideology." His exposition of this thesis offers absorbing reading. Oehser, Paul H. The Smithsonian Institution. New York: Praeger Publishers, 1970. vii + 275 pp.; $8.95. Paul Oesher, a former Public Relations Officer for the Smithsonian Institution and chief of the Smithsonian Press, has drawn upon his lengthy and extensive acquaintance with all facets of the Institution's history and current operations to produce this volume for the Praeger Library of U.S. Government Departments and Agencies. After briefly recapitulating the story of the Smithsonian's founding and its early years under Joseph Henry and S. F. Baird, Oesher describes the complex organization and functions of the Institution, its many buildings, the sources of its financial support, and assesses its past achievements and possible future role. The book is a useful descriptive guide for those interested in an overall grasp of the Smithsonian's history and functions. Rose, Hilary, and Steven Rose. Science and Society. London, England: The Penguin Press, 1969. xviii + 294 pp.; ?2.50 50s. Hilary Rose, a sociologist at the London School of Economics, and Steven Rose, a Professor of Biology at the Open University, are founder-members of the British Society for Social Responsibility in Science. The Roses' central thesis in this book is that "the continuance of the present structure of . . . scientific administration in Britain is irreconciliable with the goals of creating an open, accessible, and man-centered science, nor yet of one which is effectively planned according to technocratic criteria. In order to achieve these goals, the decisionmaking processes need to be opened at all levels." The authors explore this thesis by examining the interactions between science and govemment in Britain since the rise of the scientific societies in the seventeenth century. The bulk of their critical analysis is centered on the administration of science by the Labour and Conservative parties since World War II, set in a comparative framework with the organization of science in other nations and the role of intemational scientific organizations such as UNESCO and CERN. The Chemistry of Life. Lectures on the History of Biochemistry. Edited, with an Introduction, by Joseph Needham. Cambridge, England: Cambridge University Press, xxx + 214 pp.; $9.50. Because of the many disciplines from which it developed and with which it interfaces, biochemistry is one of the most complex and potentially fruitful fields of study for the his-

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The J. H. B. Bookshelf torian of the life sciences. It is also one of the most untapped areas of historical study, the subject of only one book-length study (by Fritz Lieben, 1935). The present volume of eight lectures, delivered between 1958 and 1961 at Cambridge University, covers a range of topics that should be of interest to readers in diverse fields of the biomedical and chemical sciences: photosynthesis; enzymes and biological oxidations; microbiology; neurology; animal hormones; vitamins; nineteenth-century pioneers in biochemistry; and an essay on the historical foundations of modern biochemistry by Mikulas Teich, one of our few professional historians of biochemistry.

375

Index FALL 1971

Abderhalden, Emil, 12, 22 Account of the Regular Gradation in Man and in Different Animals and Vegetables, Charles White, 322-323 Adams, Paul, 112-113 Adelmann, 226 Agricultural chemists, 26-30 Allele, 154 Allelomorph, 154 Allen, Garland, 66 Animal Chemistry, Justus von Liebig, 20, 253, 261 Animal heat: Lagrange's theory of, 245-248 Animal respiration, 20 Anthrax, 14-15 Anthropology of Sir William Lawrence, 322-330 Apafthy, Stefan, 276, 280-281, 290 Aromatari, 228 Astbury, W. T., 140-141 Athias, Marck, 289 Auto-attraction, 165 Auto-synthesis, 165 Babcock, Stephen M., 27-28 "Background to Eduard Buchner's Discovery of Cell-Free Fermentation, The," Robert Kohler, 35-61 Baker, Henry, Philosophical Transactions of the Royal Society, 326 Balfour, Francis, 278-279 Barcroft, Joseph, 66, 92 Barnard, Chester, 111-112 Barral, 266 Baruino, 9 Bassi, Agostino, 13

Bayliss, William, Principles of General Physiology, 117 Beard, John, 279 Beccaria, 247-248 Beddall, Barbara, 340 Behring, Emil von, 15-16, 46-47, 50 Bergmann, Max, 22 Beriberi, 1, 3, 6-8, 16; Takaki on, 6-7; Eijkman on, 8; Voderman on, 8-9 Bernal, J. D., 79-80, 138, 139 Bernard, Claude, 66, 81, 86 Bertanlanffy, Ludwig von, 65-66 Berthelot, Marcelin: on fermentation, 38 Bertrand, 372 Bethe, Albrecht, 281, 290 Bidder, F., 284; and C. Schmidt, Die Verdauungssaeft und der Stoffweschsel, 267 Bielschowsky, Max, 290 Billings, Susan M., "Concepts of Nerve Fiber Development, 18391930," 275-305 Biochemistry: and zymase, 35-37 Biology, molecular, 149-170; neglect of Muller's role in, 168-170 Birch, Thomas, 227; History of the Royal Society, 226 Bischoff, 266 Bjerknes, V., 134 Blood, A Study in General Physiology, J. H. Henderson, 92, 99, 104 Blood, human, alignment chart for, 95 Blood, mammalian, Cartesian nomogram for, 94 Blum, Harold, Time's Arrow and Evolution, 125

377

INDEX

Blumenbach, Johann Friedrich, 351-353 Blyth, Edward, 344-347, 358 Body weight: unit of, 254-257 Bohr, Christian, 88-89 Bohr, Niels, 122; on molecular biology, 152 Boltzmann, L., 134-135 Borelli, 237 Bosanquet, Bernard, 76 Boussingault, J., 260, 266 Bowler, Peter J., "Preformation and Pre-existence in the Seventeenth Century: A Brief Analysis," 221244 Braus, Hermann, 296-297 Bridges, C. B., 157-158 Brieger, L., 42, 51 Brillouin, L., 128 Brinton, Crane, 68 Bro?ek, Josef, "USSR: Current Activities in the History of Physiology," 185-208 Brush, Stephen, 121 Buchner, Eduard, 35-61; discovery of zymase, 53-61 Buchner, Hans, 40, 53-61; and immunochemistry, 42-53 Buffon, 223; pangenesis theory of, 353-354 Bunge, Gustav von: and synthetic diets,, 11-12 Burrows, Montrose, 302 Cajal, 276, 285-294 Cannon, Walter, 67, 87 Carlson, Elof Axel, "An Unacknowledged Founding of Molecular Biology: H. J. Muller's Contributions to Gene Theory, 1910-1936," 149170 Carpenter, W. B., Principles of Human Physiology, 251 Cartesian nomogram for mammalian blood, 94 Casal, Gaspard: on pellagra, 9, 19 Castle, 155 Cell-free fermentation, 35-61 Chamberland, C. E., 46 Chambers, Robert, Vestiges of the Natural History of Creation, 348, 349 Cheadle, W. B., 19 Chemistry of Life, The. Lectures on

378

the History of Biochemistry, Joseph Needham, review, 374-375 Chemists, agricultural, 26-30 Chossat, C., 267 Christiansen, Johannes, 88-90 Cigna, 246-248 Clark, Ronald: essay review of J. B. S.: The Life and Work of J. B. S. Haldane, 171-183; essay review of The Huxleys, 171-183 Clostridium botulismum, 19 Coghill, George E., 303 Cohn, Ferdinand, 14 Cohnheim, Otto, 22 Cole, F. J., 225 "Concepts of Nerve Fiber Developments, 1839-1930," Susan M. Billings, 275-305 "Confficts of Concepts in Early Vitami Studies," Aaron J. Ihde and Stanley L. Becker, 1-33 Corcos, Alain F., "'Fontenelle and the Problem of Generation in the Eighteenth Century," 363-372 Crick, Francis, 120, 142-143, 146 Croone, William, 225-227, 230 Cruickshank, William, 265; Experiments on the Insensible Perspiration of the Human Body Showing its Affinity to Respiration, 265 Darlington, C. D., 138, 319-320, 330; Darwin's Place in History, 328 Dart, Raymond A., 304 Darwin, 336-339, 342-343; The Descent of Man, 323, 327, 337-338 "Darwin, Malthus, and Selection," research note, Sandra Herbert, 209-217 Darwinism, Alfred Russel Wallace, 343 Darwin's Place in History, C. D. Darlington, 328 Davis, Marguerite, 29 Day, G. E., 270 de Beer, Gavin, 210-212 Deficiency diseases; Follis on, 18 De Generatione Animalium, William Harvey, 224 deGraaf, 227, 229 Delbriick, M., 120-121, 168 de Maeyer, L., 142 Descartes, 236-237

INDEX Descent of Man, The, Darwin, 323, 327, 337-338 Die Verdauungssaefte und der StoffF. Bidder and C. wechsel, Schmidt, 267 Diet: synthetic, balance 10-12; studies, 263-273 Dietaries, 257-263 Digby, Kenelm, Two Treatises, 229 diMattei, 45 Disease: germ theory of, 13-18, 4142; toxins as cause of, 18-19 Dissertation on the Food and Discharges of the Human Body, Bryan Robinson, 264 D'Ocagne, 96 Dohrn, Anton, 279-280 Donham, Wallace, 103 Donnan, F. G., 145; "The Mystery of Life," 126-127 Douglas, C. G., 88-90 Dounce, A. L., 141-142 Dronamraju, K. R., essay review of Haldane and Modern Biology, 171-183 Dupree, A. Hunter, 349 Eandi, G. A. F., 247 Ehrlich, Paul, 15-16 Eigen, M., 142 Eijkman, C., 16-17, 19, 26; and beriberi, 8 Eiseley, Loren, 211, 344, 347 Elsasser, Walter, 145; The Physical Foundations of Biology, 132-133 Emboitement, 221-224, 228, 230238, 240, 242-244 Emmerich, R., 45 Erepsin, 22 Ermengen, Emile van, 19 Everard, Anthony, 225-226; Novus et Genuinus Hominis et Brutique Animalis Exortus, 224 Evolutionists: and Sir William Lawrence, 336-351 Experiments on the Insensible Perspiration of the Human Body Showing its Affinity to Respiration, William Cruickshank, 265 Fabri, 228 Fachliteratur des Mittelalters: Festschrift fur Gerhard Eis, Herausgegeben von Gundolf Keil, Rainer

Rudolf, Wolfram Schmitt and Hans Vermeer, review, 219 Falta, W., 23-24 Fermentation: cell-free, 35-61; controversy over, 37-40; Berthelot on, 38; Traube on, 38; Liebig on, 3839; Pasteur on, 38-39 Feuerbach, Ludwig, 269 Fischer, Emil, 21-22, 28 Fitness of the Environment: An Inquiry into the Biological Significance of the Properties of Matter, The, L. J. Henderson, 64, 71, 73,75,78,80-81, 116 Fodor, J., 45 Follis, R. H., Jr.: on deficiency diseases, 18 "Fontenelle and the Problem of Generation in the Eighteenth Century," Alain F. Corcos, 363372 Fontenelle, Bernard de, 363-372; Histeire de l'Acad&mie Royale des Sciences, 363, 372 Food: deficiency diseases, 3-10; analysis, proximate principles in, 24-26 Forster, Josef, 26; on synthetic diets, 10-11 Foster, Michael, Textbook of Physiology, 271, 272 Fraenkel, Carl, 51 Freksa, Friedrich, 139 Funk, Casimir, 1, 3-4, 16, 26 Gaertner, August, 19 Garden, George, 242-243 Garup-Besanez, 271 Gasparin, A. E. P. de, 261-262, 269 Gassendi, 228-229 Gene, pre-Mullerian views of, 153156 Gene replication, 133-137 Gene theory, Muller's contribution to, 149-170 Gene theory, Muller's, development of, 156-167 Generation, 363-372 Genetic material, permanence of, 128-133 Genth, A. E., 262 George, Wilma, 340 Germ theory of disease, 13-18, 4142; Pasteur on, 41 Geschichte der Physiologischen

379

INDEX

Chemie, Fritz Lieben, review, 219-220 Gibbs, William, 75 Gillispie, C. C., 347 Glisson, Francis, 5 Goebel, Karl, 315 Goette, Alexander, 303 Goldberger, Joseph: on pellagra, 18 Goldscheider, Alfred, 301 Golgi, Camillo, 276, 286-287 Goodfield, June, 211 Gratarolus, 250-251 Grijns, Gerrit: and polyneuritis, 9 Grinfield, Edward, 330 Guye, Charles E., 126; PhysicoChemical Evolution, 125 Haberlandt, Gottlieb, 316-317 Hahn, Martin, 58-60 "Haldane and Huxley: The First Appraisals," Paul Gary Werskey, 171-183 Haldane and Modern Biology, essay review of, K. R. Dronamraju, 171-183 Haldane, J. S., 66-67, 88-90; Mechanism, Life and Personality: An Examination of the Mechanistic Theory of Life and Mind, 84; Organism and Environment as Illustrated by the Physiology of Breathing, 97 Hall, Diana Long, "The latromechanical of LaBackground grange's Theory of Animal Heat," 245-248 Hankins, F. F., 257 Hanson, Norwood Russell, Perception and Discovery. An Introduction to Scientific Inquiry, review, 373 Hanstein, Johannes von, 307-308 Harries, Carl, 53 Harrison, Ross, 277, 294-304 Harvey, William, 222-224, 229; De Generatione Animalium, 224 Hasselbalch, K A., 88-89 Hausermann, 12 Heisenberg, Wemer, 135-136 Held, Hans, 292-294, 301-302 Henderson, L. J., 63-113; The Fitness of the Environment: An Inquiry into the Biological Significance of the Properties of Matter, 64, 71, 73, 75, 78, 80-81, 116;

380

The Order of Nature: An Essay, 75, 76, 80, 85, 116; Blood, A Study in General Physiology, 92, 99, 104 Henle, Jacob, Pathologische Untersuchungen, 41 Henneberg, Johann Wilhelm, 25-26 Hensen, Victor, 280, 282-283 Herbert, Sandra, "Darwin, Malthus, and Selection," research note, 209-217 Heredity, 319-361 Hess, 5 Highmore, 228 Hildesheim, W., 263 Hiller, 41-42 Himmelfarb, Gertrude, 211 Hinshelwood, Cyril, The Structure of Physical Chemistry, 128 Hippocrates, pangenesis theory of, 353 His, Wilhelm, 284-285, 287, 291, 293 Histoire de l'Academie Royale des Sciences, Bernard de Fontenelle, 363, 372 History of the Royal Society, Thomas Birch, 226 HoernlI R. F. A., 77 Holmes, Frederick L., 66-67, 72, 260 Hooker, Sir Joseph Dalton, 350 Hopkins, F. Gowland, 1-2, 4, 26 Hoppe-Seyler, Felix, 39 Human blood, alignment chart for, 95 Huxley, J. S., essay review of Memories, 171-183 Huxley, T. H., Man's Place in Nature, 350 Huxleys, The, essay review of, Ronald Clark, 171-183 "latromechanical Background of Lagrange's Theory of Animal Heat, The," Diana Long Hall, 245-248 Ihde, Aaron J., and Stanley L. Becker, "Conflict of Concepts in Early Vitamin Studies," 1-33 Immunuity, 41-42; Metchnikoff on, 42; Pasteur on, 42 Hans Buchner Immunochemistry, on, 42-53 Introduction to Comparative Anatomy and Physiology, An, Sir William Lawrence, 320

INDEX

Jackson, Leila, 17 J. B. S.: the Life and Work of J. B. S. Haldane, essay review of, Ronald Clark, 171-183 Johnson, Samuel W., 27 Joravsky, David, The Lysenko Affair, review, 373-374 Jordan, Pascual, 139 Kampf ums Dasein, 44, 49 Keill, James, 263-264 Kennedy, Cornelia, 3, 30 Kitasato, S., 47 Klebs, Edwin, 15 Klebs, George, 313-314; Willkiirliche Entwicklungsanderungen bei Pflanzen, 313 Knox, Robert, 333-334; The Races of Men, 333 Koch, J., 17 Koch, Robert, 14-16, 42, 48-49 Kohler, Robert, "The Background to Eduard Buchner's Discovery of Cell-Free Fermentation," 35-61 Kolliker, Albert von, 278, 291 Krogh, August, 88-89 Kiihne, W., 36, 57 Kupffer, Carl von, 284 Lagrange's theory of animal heat, 245-248 Lawrence, Sir William, 319-361; An Introduction to Comparative Anatomy and Physiology, 320; Lectures on Physiology, Zoology, and the Natural History of Man, 321, 322, 330, 344, 350-355; anthropology of, 322-330; reception of his ideas, 330-336; and evolutionists, 336-351; development of ideas, 351-361 Lectures on Physiology, Zoology, and the Natural History of Man, Sir William Lawrence, 321, 322, 330, 344, 350-355 Leeuwenhoek, Anton van, 13, 232233 C. G., Physiological Lehmann, Chemistry, 265 Leitch, 269 Lenhossek, Milhaly von, 288-289 Leuckhart, Karl, 14 Lewis, Warren, 297-298 Lieben, Fritz, Geschichte der Physio-

logischen Chemie, review, 219220 Liebig, Justus von, 21, 261; Animal Chemistry, 20, 253, 261; on fermentation, 35, 37-39; on diet, 261 Liebig-Voit views on nutrition, 2022 Lind, James, 4-5; A Treatise on the Scurvy, 4 Lining, John, 264 Lister, Joseph, 14 Loew, Oscar, 40, 46 Loffier, Friedrich, 15 Ludersdorff, F. W., 37-38 Lunin, N., 11-12, 23 Lyell, Charles, 214-217, 349-350; Principles of Geology, 214-215, 347, 349, 357 Lysenko Affair, The, David Joravsky, review, 373-374 Macallum, Archibald, 81 Magendie, Francois, 260 Malebranche, 229, 235, 237, 243; Recherche de la v6rit6, 240 Malpighi, 223-227, 229, 231-233, 235, 243-244 Malthus, 209-217 Maly, Richard, 69 Mammalian blood, Cartesian nomogram for, 94 Mannesein, Marie, 39 Man's Place in Nature, T. H. Huxley, 350 Manson, 15 Marfan, A. B., 19 Maulitz, Russell, 67 Maxwell, J. C., 134 McCollum, E. V., 3, 10, 28-30; on phosphorus, 24 McKinney, H. Lewis, 340, 344 McLean, Franklin, 91 "Measuring Man's Needs," Jane O'Hara-May, 249-273 Mechanism, Life and Personality: An Examination of the Mechanistic Theory of Life and Mind, J. S. Haldane, 84 Mechanism of Mendelian Heredity, T. H. Morgan, A. H. Sturtevant, H. J. Muller, and C. B. Bridges, 160 Medicina Statica Hibernica, George Rye, 264

381

INDEX

Memories, essay review of, J. S. Huxley, 171-183 Mendel, Lafayette B., 29 Merycologia, sive de Ruminantibue et Ruminatione Commentariae, J. C. Peyer, 239 Metamorphosis: and preformation, 222-227 Metchnikoff, Elie: on immunity, 42, 46 Mikroskopische Untersuchungen, Carl W. Nageli, 43 Mikroskopische Untersuchungen, Theodor Schwann, 277 Milieu int6rieur, 66-67, 72, 80-81, 86, 97-99 Minerals in nutrition, SchmidtBunge views on, 22-24 Miraculum Naturae, Swammerman, 238 Molecular biology, 149-170; neglect of Muller's role in, 168-170 Moleschott, Jacob, 249-273 Monboddo, 323, 331 Moore, J. J., 17 Morgan, T. H. 130, 156-158 Morgan, T. H., A. H. Sturtevant, H. J. Muller, and C. B. Bridges, The Mechanism of Mendelian Heredity, 160 Morphogenesis, plant, 307-317 Morpurgo, B., 17 Moser, 270 Mulder, G. J., 20, 261 Muller, H. J.: contributions to gene theory, 149-170; development of gene theory, 156-167 Mutation theory, 154 "Mystery of Life, The," F. G. Donnan, 126-127 Nageli, Carl W., 40, 43-45, 49; Mikroskopische Untersuchungen, 43; Theorie der Gahrung, 54 Neal, 304 Needham, Joseph, The Chemistry of Life. Lectures on the History of Biochemistry, review, 374-375 Nencki, Marcel, 48 Nerve fiber development, 275-305; observational method, 277-295; experimental method, 295-304 "New Formations of Organs in Foundation of Plant Plants-The

382

Morphogenesis," Kraft E. Von Maltzahn, 307-317 Niles, G. M.: and pellagra, 9 Noeggerath, C. T., 23-24 Northrop, F. S. C., 100 "Notes on Source Materials: The L. J. Henderson Papers at Harvard," John Parascandola, 115118 Novus et Genuinus Hominis et Brutique Animalis Exortus, Anthony Everard, 224 Nutrition: Liebig-Voit views on, 2022; Schmidt-Bunge views on minerals in, 22-24 Nuttall, G. H. F., 45 Oehser, Paul H., The Smithsonian Institution, review, 374 "Measuring Jane, O'Hara-May, Man's Needs," 249-273 Olby, Robert, 325; "Schr8dinger's Problem: What Is Life?," 119-148 Olmsted, E. H., 98, 99 Order of Nature: An Essay, The, L. J. Henderson, 75, 76, 80, 85, 116 Organism and Environment as Illustrated by the Physiology of Breathing, J. S. Haldane, 97 "Organismic and Holistic Concepts in the Thought of L. J. Henderson," John Parascandola, 63-113 Osborne, Thomas Burr, 28, 29 Paget, James, 321 Paladino, Giovanni, 279-280 Palmer, Walter, 82, 83 Pangenes, 154 Pangenesis theory: of Hippocrates, 353; of Buffon, 353-354 John: "Organismic Parascandola, and Holistic Concepts in the Thought of L. J. Henderson," 63113; "Notes on Source Materials: The L. J. Henderson Papers at Harvard," 115-118 Pareto, Vilfredo, 104-105; Trattato di Sociologia Generale, 103, 108109 Paris, J. A., A Treatise on Diet, 250251 Parkes, E. A., 266, 270 Pasteur, Louis, 13-15, 39-40; on fermentation, 35, 37-39; on germ

INDEX

theory of disease, 41; on immunity, 42 Pathologische Untersuchungen, Jacob Henle, 41 Pauling, Linus, 139-140 Pavitch, 41-42 Pavy, F. W., Treatise on Food and Diet, 271 Payen, Anselm, 262 Pekelharing, C. A., 2-4, 7-8, 10, 16 Pellagra, 1, 3-4, 17-18; Niles on, 9; Casal on, 9, 19; Sambon on, 1718; Goldberger on, 18 Perception and Discovery. An Introduction to Scientific Inquiry, Norwood Russell Hanson, review, 373 Pereira, 275 Perrault, Claude, 241-243 Pettenkofer: on animal respiration, 20 Peyer, J. C., 240; Merycologia, sive de Ruminantibue et Ruminatione Commentariae, 239 Pfluiger, Eduard, 46 Phagocytosis, 45 Philosophical Transactions of the Royal Society, Henry Baker, 326 Physical Foundations of Biology, The, Walter Elsasser, 132-133 Physico-Chemical Evolution, Charles E. Guye, 125 Physiological Chemistry, C. G. Lehmann, 265 Physiology, in USSR, 185-208 Planck, Max, 134-135 Plant morphogenesis, 307-317 Plasmodesmen, 292-294 Playfair, Lyon, 261 Poincar6, Henri, 108, 109 Polanyi, M., 145-146 Polyneuritis, 1; Grijns on, 9 Poynton, F. J., 19 Practical Dietetics, W. Gilman Thompson, 272 Pre-existence theories, 236-243 "Preformation and Pre-existence in the Seventeenth Century: A Brief Analysis," Peter J. Bowler, 221244 Preformation: and metamorphosis, 222-227; and observation, 227236 Prichard, James Cowles, 343, 344, 355-360; Researches Into the Physical History of Mankind, 348,

355, 357, 359 Principles of GeneTal Physiology, William Bayliss, 117 Principles of Geology, Charles LyeU, 214-215, 347, 349, 357 Principles of Human Physiology, W. B. Carpenter, 251 Proximate principles in food analysis, 24-26 Psychology, in USSR, 185-208 Quetelet, Adolphe, 254-257; Treatise on Man, 256 Quincy, John, 263 Races of Men, The, Robert Knox, 333 Ranke, J., 271 Reaumur, 370 Recherche de la v6ritM,Malebranche, 240 Recommended Intakes of Nutrients for the United Kingdom, 251 Regnault, Victor, 20 Reiset, Jules, 20 Remak, Robert, 278 Researches Into the Physical History of Mankind, James Cowles Prichard, 348, 355, 357, 359 Respiration, animal, 20 Retzius, Gustaff, 288 Richards, T. W., 67 Rickets, 1-3, 5; Marfan on, 19 Roberts, S. R., 17-18 Robinson, Bryan, 265; Dissertation on the Food and Discharges of The Human Body, 264 Roger, Jacques, 222, 226, 228, 237 Rose, Hilary, and Steven Rose, Science and Society, review, 374 Rosenberg, C. E., 31-32 Rousseau, 323, 331 Roux, Emile, 39, 46-47 Royce, Josiah, 71 Russett, Cynthia, 104-106 Rye, George, Medicina Statica Hibernica, 264 Sachs, Julius, 311-313; Stoff und Form der Pflanzenorgane, 311 Salmonella enteTitidis, 19 Saluces, 246 Sambon, Louis, 17-18 Sanctorius, 263, 264 Scharling, 266

383

INDEX

Schmidt-Bunge views on minerals in nutrition, 22-24 Schmidt, C., 38 Schonlein, Johann, 13 Schrodinger, Erwin, 121-128; What Is Life?, 122-123, 132, 136, 143, 146-147, 151, 153, 168 "Schrbdinger's Problem: What Is Life?," Robert Olby, 119-148 Schultze, Oskar, 281 Schwann, Theodor, 37, 275, 278; Mikroskopische Untersuchungen, 277 Science and Society, Hilary Rose and Steven Rose, review, 374 Scurvy, 1-5; treatment of, 4; Stewart on, 17 Sedgwick, Adam, 280 Sellards, Andrew, 83 Shellshear, John L., 304 Sherrington, 87 "Sir William Lawrence (1783-1867) A Study of Pre-Darwinian Ideas on Heredity and Variation," Kentwood D. Wells, 319-361 Smithsonian Institution, The, Paul H. Oehser, review, 374 Socin, Carl A., 11-12, 23 Sorokin, 109 Stewart, C. P.: on Scurvy, 17 Stoff und Form der Pflanzenorgane, Julius Sachs, 311 Stohmann, Friedrich, 25 Structure of Physical Chemistry, The, Sir Cyril Hinshelwood, 128 Sturtevant, A. H., 157 Swammerdam, Jan, 233-235, 237240; Miraculum Naturae, 238 Synthetic diets, 10-12 Takaki, Kanehiro: on beriberi, 6-7 Template concept, 137-143 Textbook of Physiology, Michael Foster, 271, 272 Theorie der Gahrung, Carl W. Nageli, 54 Thiersch, C., 41 Thompson. W. Gilman, Practical Dietetics, 272 Thomsen, Julius, 67-68 Thomson, R. D., 260 Thomson, Thomas, 265 Thomson, William, 125 Time's Arrow and Evolution, Harold Blum, 125

384

Toulmin, Stephen, 211 Tournefort, 365-367 Toxins as cause of disease, 18-19 Trace nutrient concept, 12-26 Trattato di Sociologia Generale, Vilfredo Pareto, 103, 108-109 Traube, Moritz: on fermentation, 38 Treatise on Diet, A, J. A. Paris, 250251 Treatise on Food and Diet, F. W. Pavy, 271 Treatise on Man, Adolphe Quetelet, 256 Treatise on the Scurvy, A, James Lind, 4 Troland, H. J., 138 Trypan red, 15-16 Two Treatises, Sir Kenelm Digby, 229 Ober Organbildung im Pflanzenreich, Hermann Vochting, 308 "Unacknowledged Founding of Molecular Biology: H. J. Muller's Contributions to Gene Theory, 1910-1936, An," Elof Axel Carlson, 149-170 Unit-character, 154 Unit factor, 154 "USSR: Current Activities in the History of Physiology and Psychology," Josef Brolek, 185-208 Van Amringe, William, 334-335 Variation, 319-361 Vassalli-Eandi, A., 256 Vauquelin, L. N., 265 Vedder, E. B., 16, 19 Vestiges of the Natural History of Creation, Robert Chambers, 348, 349 Vitamins, 1-33 Vochting, Hermann, 308-315; tYber Organbildung im Pflanzenreich, 308 Voit, Karl von, 20; on animal respiration, 20 von Gundolf Keil, Herausgegeben, Rainer Rudolf, Wolfram Schmidtt and Hans Vermeer, Fachliteratur des Mittelalters: Festschrift fur Gerhard Eis, review, 219 Von Maltzahn, Kraft E., "New Formation of Organs in Plants-The

INDEX

Foundation of Plant Morphogenesis," 307-317 Vorderman, A. G.: and beriberi, 8-9 Wald, George, 78-80 Waldeyer, H. W. G., 276 Waldschmidt-Leitz, E., 22 Wallace, Alfred Russel, 339-343, 357-358; Dar-winism, 343 Walton, E. T. S., 122 Weiss, Paul, 127 Wells, Kentwood D., "Sir William Lawrence (1783-1867) A Study of Pre-Darwinian Ideas on Heredity and Variation," 319-361 Werskey, Paul Gary, "Haldane and Huxley: The First Appraisals," 171-183 What Is Life?, Erwin Schr6dinger,

122-123, 132, 136, 143, 146-147, 151, 153, 168 White, Charles, Account of the Regular Gradation in Man and in Different Animals and Vegetables, 322-323 Whitehead, Alfred North, 65 Willkgrliche Entwicklungsanderungen bei Pflanzen, George Klebs, 313 Willstatter, R., 54, 57-58 Winkler, C., 7-8, 16 Wolff, 223 Wundt, 262 Zirkle, Conway, 328 Zymase: importance for biochemistry, 35-37; discovery, and Eduard Buchner, 53-61

385