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The Inspiration of Lamarck's Belief in EvolutionAuthor(s): Richard W. Burkhardt, Jr.Source: Journal of the History of Biology, Vol. 5, No. 2 (Autumn, 1972), pp. 413-438Published by: SpringerStable URL: http://www.jstor.org/stable/4330583 .

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The Inspiration of Lamarck's Belief in Evolution*

RICHARD W. BURKHARDT, JR.

Department of History University of Illinois at Urbana-Champaign

Jean-Baptiste Lamarck had already reached his midfifties when he first came to believe in evolution. Though the change in his thought was an important one, it is not clear that this change should be regarded as an example of extraordinary intellectual flexibility for a scientist of that age. Prominent in Lamarck's coming to believe in evolution was his refusal to relinquish certain major concepts which he had cherished for a long time and which were coming under increasing attack at the end of the eighteenth century. In this paper I intend to identify the major elements of continuity and change in Lamarck's thinking at the turn of the century and to offer an explanation of just how his belief in evolution was initially inspired.

Three particular distinctions which are especially useful in analyzing the development of Lamarck's evolutionary thought should help make clear what the present paper is (and is not) about. The first is the distinction between the broad foundations on which Lamarck's biological and evolutionary thought was based and the immediate reasons in the very last years of the eighteenth century for his coming to believe in evolution. The second is the distinction between the set of specific problems that caused him to come to believe in evolution and the broader set of problems, not immediately connected with the first set, that his view of evolution came to encompass. The third is the distinction between his belief that evolution takes place and the particular mechanisms he offered to explain how evolution takes place. These distinctions, which have been made far too rarely in studies of Lamarck's thought, should help in understanding the problem that is the focus of this paper, namely, just what it was that inspired Lamarck's belief in evolution.

*An abbreviated version of this paper was read at the meeting of the History of Science Society in New York on December 29, 1971. Journal of the History of Biology, vol. 5, no. 2 (Fall 1972), pp. 413-438.

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RICHARD W. BURXHARDT, JR.

In the discours d'ouverture that he delivered to his students at the Mus6um d*histoire naturelle in 1800, the discours in which he first began setting forth his evolutionary views, La- marck provided a framework within which we may assess the nature of the restructuring that took place in his thought when he changed from a belief in the immutability of organic forms to a belief that all the different forms of life have been derived gradually from the very simplest ones. He identified three broad topics which he said ought to be considered if one were to study natural history in a profitable manner. These were

The major distinctions that nature herself seems to have established amidst the immense series of her productions; the path or order she seems to have followed in forming [these productions]; and the singular relations she has caused to exist between the ease or difficulty of their multiplication and their particular nature.'

To rephrase these topics slightly, Lamarck had in mind: (1) The basic differences between the inorganic and organic

realms, and within the organic realm, between the plants and the animals.

(2) The natural relations among nature's productions as evidenced by the degradation of complexity of organization displayed in both the plant and the animal scales (as of 1800, Lamarck had a phylogenetic explanation of these scales).

(3) The balance or economy of nature. With one critical exception, Lamarck did not change his

views significantly on any of the above topics when he came to believe in evolution. The exception, related to the first topic, was his coming to believe that life could be produced from non-life. As for the natural arrangement of nature's productions, Lamarck in the 1790's was finding more evidence to support a view that he had held for a long time: that within each of nature's kingdoms a natural classification of beings would conform to a scheme that was essentially linear. With respect to the concept of the balance of nature, Lamarck simply continued to hold a view of the well-ordered interrelations of things that was commonly held in the late eighteenth century. His acceptance of this view was perfectly in accord with his general thinking about nature's operations. The appearance of the concept of the balance of nature in his discours of 1800

1. J. B. Lamarck, "Discours d'ouverture, prononc6 le 21 flor6al an 8," in Syst#ine des animaux sans vertrbes (Paris, 1801), pp. 1-2. All the translations in this paper are the author's own.

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Lamarck's Belief in Evolution

thus represented no major conceptual change on his part. The concept did, however, have a prominence in the discours of 1800 that it had not had in any of his previous writings. Sig- nificantly, 1800 was the first time that Lamarck mentioned the balance of nature in conjunction with the issue of species extinction.2

I believe two changes in particular were critical for the general change that took place in Lamarck's thinking at the turn of the century. One was his coming to believe that life could be produced from non-life. This was fundamental for the broad view of evolution he developed. Though others before him had believed in spontaneous generation without believing in evolution, it appears that Lamarck's new belief in spontaneous generation-or direct generation, as he preferred to call it -was crucial for the development of his evolutionary views. The other was his coming to believe in the mutability of species. I would argue that the idea of spontaneous generation and the idea of species mutability were logically independent of one another as Lamarck initially developed them, but that they were inspired at roughly the same time, perhaps even by the same general issue-that of extinction. Other writers have already commented on Lamarck's thoughts on the issue of extinction, but I think that it is possible to be much more precise concerning just how this issue was instrumental in the inspiration of his new evolutionary views.

It is not surprising that there have been a variety of explanations of how Lamarck came to believe in evolution.3 He

2. Ideas concering the balance of nature did appear in Lamarck's opening discours of 1798 and 1799 in his discussion of nature's checks on insect populations, but the issue of whether species nmight not always be conserved was not considered. This discussion was in fact taken directly from G. A. Oliver, "MWmoire sur l'utilit6 de 1'6tude des insectes, relativement A l'agriculture et aux arts," Journal d'histoire naturelle 1 (1792), 33-56. Lamarck, "Discours pr6liminaire pour le cours de l'an six. lu le 14 flor6al an 7 [3 May, 1799]," Mus6um national d'histoire naturelle (Paris), MS 2628 (2). This important manuscript was discovered recently among the Mus6im papers by Yves Laissus, Conservateur of the Museum library. Henceforth this will be cited as "Discours de I'an VII."

3. Interpretations of how Lamarck came to believe in evolution have been offered by Marcel Landrieu in Lamarch: le fondateur du trans- formisme (Paris: 1909); Henri Daudin, Cuvier et Lamarck: les Classes zoologiques et L'idde de s6rie animale (1 790-1830), 2 vols. (Paris: 1926); Louis Roule, Lamarck et l'interpr6tation de la nature (Paris: 1927); Emile Guy6not, Les Sciences de la vie aux XVII' et XVIIP' sikcles (Paris: 1941); Charles C. Gillispie, "The Formation of Lamarck's Evolutionary Theory," Archives internationales d'histoire des sciences, 9 (1956); 323-338, and "Lamarck and Darwin in the History of Science," in Bentley Glass et al.,

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himself left us only a sketchy, highly rationalized account of the development of his general views. He was also appallingly negligent in indicating the contemporary thinkers whose ideas stimulated creative responses on his part. As a result, most studies of Lamarck have failed to identify what might be called his intellectual habitat-the intellectual micro-climate within the broader climate of scientific ideas of the period. My interpretation of the development of Lamarck's evolutionary thought is in part the result of an attempt to identify that particular intellectual context. The extraordinary diversity of Lamarck's activities in the period just before 1800 and the difficulty of estimating just when he changed his mind on the subject of organic mutability have also played a part in the variety of explanations of how Lamarck came to believe in evolution. I believe that critical additions can be made on both of these points, and that, once these additions are made, there is an explanation of the origin of Lamarck's belief in evolution that fits them perfectly.

Charles C. Gillispie has maintained that from 1793 to 1800 LamarckWs thoughts were "absorbed in writings on chemistry, geology, and meteorology."4 This would admittedly have been enough to keep most people busy, but it is in fact an incom- plete picture of Lamarck's activities for the period in question. Though most of Lamarck's publications during the period were devoted to physico-chemical topics, he did not in the meantime neglect completely his duties as professor of invertebrate zoology at the Museum. On the contrary, he was engaged in some

eds., Forerunners of Darwin: 1745-1859 (Baltimore, 1959), pp. 265-291; John C. Greene, "The Kuhnian paradigm and the Darwinian Revolution in Natural History," in Duane H. D. Roller, ed., Perspectives in the History of Science and Technology (Norman, Okla., 1971), pp. 3-25; and M. J. S. Hodge, "Lamarck's Science of Living Bodies," Brit. J. Hist. Sci. 5 (1971), 323-352.

Very briefly, the explanations presented have been that Lamarck's geological thinking was central to the restructuring of his biological thought (Landrieu, Daudin, and Greene), with the issue of extinction being of special importance (Daudin and Greene); that he was critically impressed by the ideas of Cabanis, which reawakened for him the sorts of views Buffon had been advancing some years earlier (Roule, followed by Guy6not); that his evolutionary theory emerged from his physico-chemical speculations in a transfer of thoughts on mineral mutability to organic species (Gillispie); and that seeing the gradation of complexity of the animal scale forced him to think that nature had produced the different animals successively (Lamarck's retrospective account in the Philosophie zoologique, accepted by Hodge).

4. Gilhispie, "The formation of Lamarck's evolutionary theory," p. 325.

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important work on invertebrate classification, especially toward the end of the period. Particular aspects of this work, together with certain thoughts on the nature of the very simplest animals and the problem of generation, posed the issues that were responsible for the change that took place in his thinking.

The most critical change in Lamarck's thinking occurred, I believe, between the spring of 1799 and the spring of 1800. The evidence for this is not entirely conclusive, since La- marck's last definitive statement on the immutability of organic forms was made in 1794.5 My argument for the importance of the period from 1799 to 1800 is based largely on negative evidence from the discours preliminaire Lamarck delivered to his students on May 3, 1799.6 In this discours there is no discussion of organic mutability,7 and there is an indication that Lamarck had not yet come to believe in spontaneous generation.8 This seems, furthermore, to be basically the same discours that Lamarck had been giving since as early as 1796.9 It appears that in the course of at least four years he had not revised it significantly. Between 1799 and 1800, however, he rewrote it completely; in the new discours of 1800 the concept of organic mutability played a prominent role.

The question now to be considered is whether there was anything in particular in the period 1799 to 1800 that might have inspired this restructuring of Lamarck's thinking. There are perhaps two basic reasons why the answer to this question has not been given previously in just the way that I intend to give it here. The first is that upon reading Lamarck's major statements of his evolutionary views-in his Recherches sur l'organisation des corps vivans (1802), his Philosophie zoologique (1809), or the introduction to his Histoire naturelle

5. J. B. Lamarck, Recherches sur les causes des principaux faits physiques, 2 vols. (Paris, 1794), II, 213-214. The comments that Lamarck made on generation in M#moires de physiques et d'histoire naturelle (Paris: 1797), P. 270, do not constitute proof that Lamarck still believed in species fixity in 1797.

6. "Discours de P'an VII." 7. Lamarck does state in the discours that "One cannot help but admire

nature's infinite resources in the variety of means she employs to diversify, multiply, and conserve her productions; that is to say, the species and kinds which constitute them" ("Discours de l'an VII," p. 2). The rest of the discours provides no indication, however, that this statement is to be taken in an evolutionary sense.

8. See below, p. 432. 9. See "Nouvelles litt6raires," Magasin encyclop6dique, 2 ann6e (1796),

I, 285, for a brief summary of Lamarck's introductory discours in 1796. To the best of my knowledge this useful source has previously escaped the attention of Lamarck scholars.

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des animaux sans vertibres (1815)-one is likely either to forget or never even to realize where Lamarck's greatest expertise as an invertebrate zoologist lay. The second is that upon looking over Lamarck's record of publication one would never guess what it was that his contemporaries were eagerly await- ing from him in 1799.

Lamarck's greatest expertise as an invertebrate zoologist lay in his work as a conchologist. When he was chosen as professor of invertebrate zoology at the Mus6um, his only real claim to competence in that field was from his work as a col- lector of shells. In 1799 it was not a Philosophie zoologique that his contemporaries were expecting from him, nor any of the other works he published in the 1800s. It was rather a work to be entitled hlemens de conchyliologie, promised in a memoir that was read at the Institut on December 11, 1798, and published in the MWmoires de la Soci&t6 d'Histoire naturelle de Paris in 1799.10 Lamarck explained his projected work by saying: "It seemed to me indispensable to give to the public, and especially to the students following my lessons at the Museum, . . . a work in which I plan to present a concise exposition of principles relative to the study of shells, and to their distinction into families, genera, and species." 11

Contemporary interest in Lamarck's proposed conchology was high, but not simply because the systematic exposition of any part of nature's productions would have inspired interest or because the collecting of shells was popular in Paris at the time.12 Lamarck specified the particular importance of his work as follows:

We are at present convinced that the knowledge of shells is important, not only because we must not neglect the study of any of nature's productions, and because the form of a shell is in general an indication of the form of the mollusc that produced it, but also because it is very important to search for and determine the living or marine analogs of the large number of fossil shells that are found buried in 10. Lamarck, "Prodrome d'une nouvelle classification des coquilles,

comprenant une r6daction appropri6e des caract6res g6n6riques, et 1'6tab- lissement d'un grand nombre de genres nouveaux, lu A l'Institut national le 21 frimaire an 7 [11 Dec., 17981," MWmoires de la Soci6t6 d'Histoire naturelle de Paris, 1 (1799), 63-91.

11. Ibid., pp. 66-67. 12. According to Pierre Denys de Montfort, who owned one of the major

collections of shells in Paris at the time, more than six hundred dealers were making a good living in Paris at the turn of the century selling shells. Denys de Montfort, Conchyliologie systematique, et classification m6th- odique des coquilles . . . (Paris: 1810), II, 96.

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Lamarck's Belief 'm Evolution

the very middle of our vast continents. Now, the conse- quences that can be drawn from these determinations are of such a great interest for natural history, and especially for the theory of the globe we inhabit, since they can enlighten us on the nature of the changes that the different parts of its surface have successively undergone, that we perceive that any errors in these determinations would be very preju- dicial to our researches in this interesting part of natural history. It is thus only by the accuracy of the determination of those of our living shellfish which are analogous to the fossils of our continents that we will be able to obtain solid and well-founded deductions on several important points concering the theory of our globe.'3

These claims, though not novel, did not fail to attract the attention of Lamarck's contemporaries.14 Barthelemy Faujas de Saint-Fond, professor of geology at the Museum, expressed in 1799 his eagerness to see Lamarck's conchology. As Faujas put it, an important key to the history of the earth was an exact knowledge of fossil forms. This, however, had previously been hindered by "the incertitude which has always reigned over the knowledge of shells due to the lack of a good method- ical work on this subject." 15 Lamarck was intending to provide just such a work. Faujas, it must be noted, looked forward to Lamarck's conchological studies with one question in particular in mind: what light would these studies shed on the question of species extinction?

Despite the perceptive suggestion made by the historian Henri Daudin, it has not generally been appreciated how critical the issue of extinction was to Lamarck late in the 1790's.'6 The way this issue was posed to him and the way he re- sponded to it deserve further analysis. It was in the latter half of the 1790's that the issue of extinction was dramatized by Cuvier's researches on the fossil quadrupeds. When Cuvier read his first memoir on the subject, he was cautious in draw- ing his conclusions, but he did suggest that the forms of life

13. Lamarck, "Prodrome d'une nouvelle classification des coquilles," pp. 63-64. 14. For an earlier, similar statement concerning the importance of conchology, see J. G. Bruguiere, "Conchyliologie," Encyclop6die m6thodique. Histoire naturelle des Vers, 1 (1792), 5-9. 15. Barth,lemy Faujas de Saint-Fond, HistoiTe naturelle de la Montagne de Saint-Pierre de Maestricht (Paris: 1799), p. 28. This work was published in sections. The discours prfliminaire, from which the quote is taken, appeared in 1799. 16. Daudin, Cuvier et Lamarck, II, 205-210.

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RICHARD W. BUXRHARDT, JR.

currently existing on earth had replaced others which had been totally destroyed by some catastrophe.17 What even Daudin did not appreciate fully was just how much conchology was involved in the debate about extinction at this time.'8 Cuvier was not the only one raising the issue of extinction. Though he used primarily the evidence of fossil bones to support his contention, Cuvier also observed that "several learned conchologists maintain that none of the shells presently existing in the sea are to be found among the numerous fossils of which our continents are full."'9 He made this observation in the memoir on the living and fossil species of elephants that he read at the first public session of the Institut. Significantly enough, however, he chose to omit the statement from the published versions of the memoir. Historians of science may have been thrown off the track by this omission. It is evident, though, that for the conchologist in Paris in the 1790's the lines of debate were drawn.

These lines in fact could not have been drawn more clearly. Some conchologists maintained that no fossil shells had any living counterparts.20 But just the opposite view, the idea that

17. Georges Cuvier, "M6moire sur les espkces d'6l6phans vivantes et fossiles. lu & la S6ance publique de l'institut national, le 15 germinal an 4, 14 April, 1796]" Mus6um national d'histoire naturelle, MS 628, p. 15 (unnumbered). This manuscript is not identical either to the "extract" of it that appeared in Magasin encyclopddique, 2' annie (1796), III, 440-445, or to the memoir that appeared in M6moires de l'Institut (Classe math. phys.), 2 (1799), 1-22.

18. Daudin never saw a copy of Lamarck's 'Prodrome" (Daudin, Cuvier et Lamarck, II, 305), and he was evidently unaware of the remarks of Cuvier and Faujas on the interest of fossil shells.

19. Cuvier, "Memoire sur les esp6ces d'6l6phans," Museum MS 628, pp. 14-15 (unnumbered).

20. I have not been able to identify which conchologists were maintaining that no fossil shells had any living counterparts. According to Faujas de Saint-Fond, the idea was advanced by a small number of naturalists (Faujas, Hut. nat. de Maestricht, p. 123). The man who probably had the finest conchological collection in Paris was L.-C.-M. Richard (1754-1821), who is known now primarily for his work as a botanist, but who was recognized by his contemporaries as an expert conchologist as well. Had Richard advanced the view in question he probably would have been named. On Richard, see Ed. Lamy, "Note sure une collection conchyliol- ogique du commencement du xix sibcle," Bull. Mus. nat. Hist. nat., 21 (1915), 101-104. Other collectors of note in the period besides Brugui6re, Faujas, Lamarck, and Richard were Denys de Montfort, Aubert, Dedr6e, Hwass, Maug6, Paris, Pech, Poissonier, Rossi, and Sollier. See Faujas de Saint-Fond, Essai de gdologie, ou Mdmoires pour servir a l'histoire naturelle du globe, I (Paris: 1803), pp. 42-43; Denys de Montfort, Conchyliologie syst6matique, II, 96; and Ed. Lamy, Les Cabinets d'histoire naturelle en France au xvfiii' sicle (Paris: 1930).

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all fossil shells have living counterparts, had also been expressed recently, and by the man who was probably the lead- ing conchologist of the day-Jean-Guillaume Bruguiere.21 Bru- guiere, a good friend of Lamarck, died late in 1798 after having been away from Paris for six years on a scientific expedition. Lamarck had been entrusted with the continuation of Brugui- ere's part of the Encyclop6die methodique during his friend's absence. It is perhaps no coincidence that Lamarck's memoir on conchology was read shortly after the news of Bruguiere's death reached Paris.22 By 1799 it was Lamarck who was looked upon as the man with the expertise in conchology through which the issue of extinction among the shellfish was to be resolved. I believe that it was the specter of species extinction, as posed by the differences between fossil and living forms, that drove Lamarck to his belief in species mutability in the first place.

There were basically three ways of explaining the differences between fossil and living forms. Cuvier identified the options in a paper of 1801: "It is a question of finding out whether the species that existed [in the earth's distant past] have been entirely destroyed, or if they have only been modified in their form, or if they have simply been transported from one climate to another."' 23 Cuvier himself favored the first of these al- ternatives, at least initially.24 Brugui6re had favored the third. Lamarck, unwilling to call upon a major catastrophe to explain nature's processes, relied in part on the third and readily em- braced the second, namely, the idea that in the course of the earth's history species have been modified.

To appreciate fully the step Lamarck took, it is necessary to grasp the reasons behind his unwillingness to accept the

21. J. G. Brugui6re, "Cerite," Encyclopddje mdthodique. Vers, 1 (1792), 472. For a useful but by no means complete treatment of Brugui&re (1750- 1798), see Georges Cuvier, "Extrait d'une notice biographique sur BruguiMres [sic]," Recueil des dloges historiques . . . par G. Cuvier, nouvelle edition (Paris: 1861), III, 357-372. 22. Cuvier's article on Brugui6re in the Biographie universelle gives the date of Bruguiere's death incorrectly as 1799, an error which has been repeated in several subsequent biographical notices. Brugui6re died at AncBne on October 3, 1798. See G. A. Olivier, Voyage dans l'Empire othoman, l'Egypte et la Perse, VI (1807), 515-517. 23. Georges Cuvier, "Extrait d'un ouvrage sur les esp6ces de quadrupMdes dont on a trouv6 les ossemens dans l'int6rieur de la terre, adressd aux savans et aux amateurs des sciences," Magasin encyclop6dique, 7e ann6e (1801), I, 64. 24. Cuvier soon stopped referring to the occurrence of a global catastrophe, and he eventually relied on migrations to explain the repopulation of areas following the occurrence of nonglobal catastrophes.

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idea of large-scale species extinction as the result of some sort of major catastrophe. Neither the idea of a catastrophe nor the idea of species extinction was compatible with the operations of nature as he conceived them. Catastrophism he scorned as unscientific: "A universal upheaval which necessarily reg- ularizes nothing . . . is a very convenient means for those naturalists who wish to explain everything and who do not take the trouble to observe and study the processes of nature." 25 Lamarck's own view of nature's operations was wholly uni- formitarian. As for the idea of species extinction, this did not sit well with the traditional view he held of the balance or economy of nature. A belief in nature's wisdom seems to have generally guided his thinkilg.26 In his discours of 1800 he spoke to his students of the "wise precautions of nature" through which "everything remains in order":

No species predominates to the point of bringing about the ruin of another, except perhaps in the most complex classes, where the multiplication of individuals is slow and difficult.

. . In general the species are preserved.27

Camille Linoges has recently suggested that behind Lamarck's reluctance to admit species extinction, behind his acceptance of traditional ideas concerning nature's balance, was a "con- ception of life as a principle of order and organization":

If a species came to disappear in [the struggle between species], this would require that life itself be able to intro- duce disorder into the general realm of nature, which in the Lamarckian perspective is a contradiction in terms.28

I find this to be an attractive explanation of Lamarck's reluctance to admit species extinction, but it may grant to La- marck's thinking a greater unity than is in fact demonstrated by his writings. Lamarck, at any rate, never expressed himself in such terms. There is a more direct way of explaining his

25. J. B. Lamarck, "Sur les fossiles," Systgme des animaux sans vert0bres, p. 407.

26. I make this statement fully aware of the fact that when Lamarck considered the subject more analytically he concluded that nature was a non-intelligent order of things, something "which acts only by necessity, and which can execute only what it does execute." See Lamarck, Histoire naturelle des animaux sans veWtAbres, I (Paris: 1815), 323, and "Nature," Nouveau Dictionnaire d'histoire naturelle, 22 (1818), 363-399.

27. Lamarck, "Discours d'ouverture, 1800," SysUme des animaux sans verthbres, p. 23.

28. Camille Limoges, La SUlection naturelle (Paris: 1970), p. 38.

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reluctance to admit species extinction, and this, as I will attempt to show later, may also provide the key to understanding how Lamarck came to believe in spontaneous generation when he did.

A major reason that Lamarck rejected the idea of species extinction was that he simply could not imagine a natural mechanism by which extinction could take place. A large- scale catastrophe was not in his view a natural mechanism. He would tentatively grant to Cuvier that a few species of large quadrupeds might possibly have been destroyed by man. But that fate seemed unlikely for the smaller, more prolific ter- restrial species. And what of marine organisms? What, in particular, of those forms with which Lamarck, as a conchologist, was most familiar? On this topic Lamarck's conclusions were no different from those of Bruguiere.

Bruguiere maintained that the reason no one had yet found such well-known fossil forms as the ammonites and the belem- nites in the living state was that these anmals lived only in the greatest depths of the sea. In a long discussion of his reasons for believing that ammonites still existed, he came to a problem which those who believed that ammonites were extinct had not been able to answer to his satisfaction:

What causes could be adduced [for the extinction of these creatures] when it is virtually demonstrated that the tem- perature must be equal in the ocean at a great depth, and that if it is proved that [these creatures] once lived there, they must, by this reason alone, be found there Still.29

Lamarck, refusing to accept a catastrophe to explain extinction, agreed with Brugui6re. A natural mechanism by which extinction might take place was something he could not imagine.

Lamarck's 9lmens de conchyliologie never appeared as such, but aspects of his conchological studies at the turn of the century did find their place in his Syste me des animaux sans vertebres (1801). In the Systeme he added eighteen more genera to the 126 genera of shells he had already identified in his memoir of 1799. Faujas de Saint-Fond rushed quickly to the

29. J. G. Brugui6re, "Ammonites," Encyclop6die m6thodique. Vers, I (1789), 32. For Lamarck's views, see Lamarck, "Sur une nouveUe esp&ce de Trigonie, et sur une nouvelle d'Hultre, d6couvertes dans le voyage du capitaine Baudin," Annales du Musdum d'Histoire naturelle, 4 (1804), 351-359; and Philosophie zoologique (Paris: 1809), I, 77. See also Stephen Jay Gould, "Trigonia and the Origin of Species," J. Hist. Biol., 1 (1968), 41-56.

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Systeme-indeed he used advance sheets that Lamarck lent him before the work was published-to answer the question whether any fossil species had living analogs. Faujas was able to identify immediately forty-one species of fossil shells with known living analogs, and he supposed that as others used Lamarck's work the list would grow.30 Lamarck himself observed that there were enough fossil species with living counterparts to discount the idea of a universal catastrophe. He acknowledged that there were many fossil forms for which there were no known living counterparts, but for many of these he could point to living species of the same genus that resembled the fossil species quite closely.31 Unwilling to admit that some major catastrophe might have caused extinction, unable to conceive of a natural mechanism by which extinction might take place, but granting that there were differences between fossil and living forns that probably would never be explained simply by the discovery of living analogs of the fossils, La- marck was quite naturally led to a belief in species mutability.

The above explanation of the inspiration of Lamarck's belief in species mutability should be contrasted with a rather similar explanation that has received some attention recently.32 The latter explanation recognizes the issue of extinction as important but stresses the centrality of Lamarck's geological theorizing for the change that took place in his biological thought. The explanation is basically as follows. Lamarck recognized that animals are adapted to their environments. Through the geological views he was developing late in the 1790's, he recognized also that environments must iMevitably change, if only ever so slowly. Thus he concluded that to remain adapted, not to become extinct, animals too had to change.

Lamarck did at times argue for organic mutability in these terms. But there are reasons for believing that that is not exactly the way he came to believe in organic mutability. No doubt part of the appeal of the explanation in question has

30. Faujas, Hist. nat. de Maestricht, pp. 124-125. By 1803 Faujas had expanded his list to fifty-six species. Faujas, Essai de gdologie, I, 58-75.

31. Lamarck, Syst.me des animaux sans vertebTes, p. 408: "It is worth remarking that among the fossil shells for which marine or living analogs are not known, there are many of them which have a form very close to shells of the same genera that are known in the marine state. They differ more or less, however, and cannot be regarded rigorously as the same species as those that are living, since they do not resemble them perfectly."

32. See Ernst Mayr, "Lamarck revisited," J. Hist. Biol. 5 (1972), 61, and Greene, "The Kuhnian paradigm and the Darwinian revolution in natural history," pp. 13, 24-25.

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been the presumed novelty of Lamarck's geological views. In fact, however, little of Lamarck's geological thinking was original. Virtually all of the major concepts of his Hydrog6ologie (1802) had been advanced by others before him.33 Lamarck began expounding his geological views in 1799, but most of these views were not new to him then. There is evidence to suggest that he held some of them in 1797, if not as early as 1794, 34and others he held earlier still.35

That Lamarck's geological theory was not novel is not to say. 33. Landrieu, Lamarck, p. 172, and Albert Carozzi (ed.) Lamarck, Hydro-

geology (Urbana, Ill., 1964), p. 8, assert incorrectly that Buffon was the only figure among Lamarck's predecessors and contemporaries who had an influence on Lamarck's geological theorizing (Carozzi's footnotes to Lamarck's text in fact suggest other contemporaries who may have been of some influence). Lamarck's Hydrogdologie (Paris: 1802) provides a prime example of how Lamarck's failure to cite contemporary thinkers has led to an exaggerated opinion of his originality. One finds, for example, that Daubenton, in a lecture delivered to students at the t.cole normale in 1795, advanced most of the concepts that were to appear a few years later as the central ideas of Lamarck's Hydrog6ologie. Daubenton, "Sur les couches du globe de la terre," Sgances des tcoles normales, Tecueillues par des stbnographes, et revues par les professeurs, nouvelle edition, 8 vols. (Paris, 1800), II, 265-290. Daubenton, to be sure, was basically following Buffon in this lecture. The major concept of Lamarck's Hydrog6ologie that is not found in Daubenton's lecture is the idea of the organic origin of much of the earth's surface. This idea was not novel either, however. The idea of the construction and shaping of the earth's surface by organic action plus the effects of water in motion is found in Antoine Baum6, Chymie exp6rimentale et raisonnde, 3 vols. (Paris, 1773), III, 301-334. Lamarck took a special interest in Baum6's work. See Lamarck, "Classes," Encyclop6die methodique. Botanique, 2 (1786), 35-36, and Recherches BUT les causes des principaux faits physiques, II, 306-309.

34. In 1797 Lamarck remarked that the sea "has successively covered the continents," but he was disinclined to discuss geological theory at the time (Memoires de physique et d'histoire natUTelle, pp. 346-347). In 1801, in describing fossils as "extremely precious monuments" for studying "the revolutions that different parts of the surface of the globe have undergone" and "the changes that living beings have themselves successively ex- perienced there," he claimed: "In my lessons I have always insisted on these considerations" (Syst&ne des animaux sans vertWbres, p. 406). Lamarck gave his first course at the Museum in the spring of 1794. There is no evidence that Lamarck insisted on the mutability of species as early as 1794 (and it is not clear that his statement of 1801 should be interpreted as claimig that). Some early lecture notes on the topic of fossil shells include simply the observation that fossil shells tell a great deal about changes on the globe's surface, in particular that the sea has covered particular points of the earth's surface for long periods of time. "Termin- ologie pour les coquilles et methodes de conchyliologie. Coquilles fossiles." Mus6um national d'histoire naturelle, MS 743 (8), p. 27. The manuscript is not dated.

35. Lamarck's thoughts on the organic origin of the minerals date from the 1780s. See Lamarck, "Classes," Encyc. mdth. Botanique, 2 (1786), 34-36.

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of course, that it was unimportant for the development of his evolutionary views. Certainly the timing of his elaboration of his geological theory corresponds quite well with his formula- tion of his evolutionary views. I would emphasize, nonetheless, the importance of his attention to conchology in this period. There are two reasons for this. The first is that he first presented his geological views to the Premi&re Classe of the Institut (in February 1799) as being based on his study of fossil shells.36 The second, which is more crucial, is that Lamarck's geological views did not by themselves necessitate a change in his biological views. Late in the eighteenth century it was widely appreciated that animals are generally suited to their environments and that in the course of geological time cli- matic changes have occurred all over the earth's surface. But this, as I have already indicated, did not leave the naturalist with only two altematives, namely, extinction or slow organic change. There was a third possibility-migration-and this was the altemative that most naturalists chose up into the late eighteenth century. The evidence that began emerging from Lamarck's conchological work was precisely the kind of evidence required to show that migration alone was unlikely to explain why modem forms of certain fossils had not been found. The connection was close between Lamarck's views on geology and his views on organic mutability. I believe it is fair to say, however, that what immediately inspired his belief in species mutability was not so much the geological views that he held in common with some of his contemporaries, but rather the work on the classification of shells that he was doing in 1799-the work in which he was the recognized leader.

One may rightly ask, if fossil shells played such an important role in the inspiration of Lamarck's belief in species mutability, as has been maintained in this paper, why are fossils not mentioned in Lamarck's opening discours of 1800? And why, furthermore, are paleontological considerations largely

36. Lamarck's memoir to the Institut was entitled "Sur les fossiles et l'influence du mouvement des eaux, consid&rs coxmme preuves du d6place- ment continuel du bassin des mers, et de son transport sur les diff6rens points de la surface du globe." Lamarck began reading the memoir at the session of February 9, 1799 and completed it February 19, 1799. The title of the memoir is given in Proc6s-verbaux des SeVances de l'Acad6mie, I, 524, 528. Some further information on the memoir is provided in a contemporary account of activities at the Institut: Lassus, "Sciences physiques," Magasin encyclopddique, 5. ann6e (1799), I, 233-234. To the best of my knowledge this account has not appeared previously in the La- marck literature.

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absent from Lamarck's later development of his theory? In answering the first question, one must begin by observing that Lamarck's discours of 1800 was not primarily an exposition of an evolutionary theory. As Lamarck observed concerning the discours when he published it in 1801 at the beginning of his Syste'me des Animaux sans Vertebres:

I have left a glimpse there of some important and philosophical views that the nature and the limits of this work have not permitted me to develop, but which I propose to take up again elsewhere with the details necessary to make known their foundation and with certain explanations which will prevent them from being abused.37

The answer to the second question will be developed later. For now it will be noted that what Lamarck's relatively few evolutionary comments of 1800 suggest is that by the time he did set forth his "philosophical views" at length (in his Re- cherches sur l'organisation des corps vivans of 1802), his view of organic change had developed along lines that were largely independent of his thoughts on the issue of extinction.

Lamarck's discours of 1800 was basically an attempt to describe the general attractions of the study of invertebrate zoology, to characterize briefly the animals in question, and in "giving an idea of the surprising gradation that exists in the composition of organization of these animals," 38 to set up the general foundations for what was to follow in later lessons, namely, a systematic exposition of the various kinds of invertebrates. We would do well to consider here some of those elements which appeared in the discours of 1800 that had not appeared in Lamarck's earlier discours or writings. It seems likely that behind several of these new elements was Lamarck's thinking about fossils and the question of extinction. One new element in 1800, for example, was the statement that species do not destroy one another but instead are generally conserved as the result of the balance of nature.89 What was most strikingly new in the discours, however, was La- marck's claim that for all the classes, orders, genera, and species in existence he could show "that the conformation of individuals and their parts, that their organs, their faculties, &c. &c. are entirely the result of the circumstances in which the race of each species has found itself subjected by nature."40

37. Lamarck, Systeme des animaux sans vertabres, p. vi. 38. Ibid., p. vi. 39. See above, n. 27. 40. Lamarck, Systene des animaux sans vertibres, pp. 14-15.

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Lamarck mentioned neither shells nor fossils in connection with this statement. What he offered instead were the web- footing of swimming birds, the claws of perching birds, and the elongated legs of wading birds as evidence of the results of the acquired effects of habit upon form. The choice is an interesting one, for these birds seem never to have been of special interest to Lamarck before. It seems that in coming to believe in organic mutability he realized he would have to account somehow for the general observation that animals tend to be admirably suited to their particular modes of existence. Using examples that had been explained previously in the framework of natural theology,41 he supplied an explanation of his own for the phenomenon: "It is not at all the form either of the body or its parts that gives rise to habits or the way of life of animals, but, to the contrary, the habits, the way of life, and all the influential circumstances which have with time formed the body and parts of the animals." 42

Though influential circumstances, not fossil shells, received Lamarck's attention in the discours of 1800, one must note that it was the evidence of fossil shells-primarily the observation that European fossils resembled tropical forms more often than temeprate forms-that Lamarck used in the first place to argue that conditions at given points of the earth's surface have changed in the course of geological time. La- marck then expanded his explanatory framework by turning the argument around and asserting that changing circumstances were responsible for the differences between fossil and living forms. He made this assertion in the appendix on fossils that he added to his Syst6me des animaux sans vertabres. Reacting specifically to the proposition that "all the fossils belong to the remains of animals or plants whose living analogs no longer exist in nature," he observed: "It is very true that of the great quantity of fossil shells gathered in the diverse countries of the earth there is yet only a very small number of species for which the living or marine analogs are known."43 Speaking in particular of those fossils which had no exact marine analogs but which did resemble closely marine species of the same genus, he continued:

41. See Pluche (Abbe Noel Antoine), Le Spectacle de la Nature, ou entretiens sur Les particulantds de l'histoire naturelle qui ont paru lee plus propres t rendre les jeunes gens curieux & a leur former l1esprit (Paris, 1782), I, 294. Lamarck owned the first edition of this work, which appeared in eight volumes (1732-1750).

42. Lamarck, Syst&me des animaux sans vertabres, p. 15. 43. Ibid., pp. 407-408.

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I agree that it is possible that among the fresh or marine shells one never finds shells perfectly similar to [these fossils] . . . I believe I know the reason for it. I am going to indicate it succinctly, and I hope that then it will be per- ceived that although many fossil shells are different from all the marine shells known, that in no way proves that the species of these shells are destroyed, but only that these species have changed in the course of time, and that presently they have different forms from those of the individuals whose fossil remains we find.44

Environmental changes, Lamarck explained, had caused living things to change their habits, and these changes in habits had in turn resulted in new organic forms and structures. This explanation, however, is not the primary concern of the present study. What is to be underlined here is the point that species mutability was Lamarck's answer to the problem posed to him by the differences between fossil and contemporary shells.

This is not all there is to the story of the inspiration of Lamarck's belief in evolution. It is worth recalling that in 1753, almost half a century before Lamarck began developing his transformist views, Buffon wrote:

If it were granted that in the animals, or even in the plants, there were, I do not say several species, but a single one which had been produced by the degeneration of another species; if it were true that the ass were only a degen- erated horse, then there would be no more limits to the power of Nature, and one would not be wrong in supposing that from a single being she knew how, with time, to derive all the other organized beings.45

It may be safely said that Lamarck's broad view of evolution was not the embodiment of this sort of reasoning-it was not basically an extrapolation from the idea of species mutability. As historians of science have only too recently begun to insist, the Philosophie zoologique was not essentially a pre- mature OrTgin of Species.

To appreciate the nature and indeed the novelty of Lamarck's evolutionary thought in the context of his own time one may compare his thinking with that of Buffon himself, or Buffon's disciple Lacepede. Buffon, some time after he wrote the state-

44. Ibid., pp. 408-409. 45. Buffon, "L'asne," Histoire naturelle, 96n6rale et particulUre, avec la

description du Cabinet du Roi, 4 (Paris: 1753), p. 382.

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ment I have quoted, came to believe that the two hundred species of modern quadrupeds had descended from a more limited number of primordial types.46 He did not come to believe, however, that all the forms of life had been derived from a single one. Nor did his disciple Lacepede, who was Lamarck's contemporary, and who set forth ideas on organic mutability in the same year that Lamarck did-1800.47 Significantly, La- cepede, like Lamarck, offered the transmutation of species as an alternative to species extinction. But Lacepede's view of organic change was not like Lamarck's. Rather, it was like Buffon's later view, with something of the later views of Lin- naeus added as well. What Lacepede supposed was that from a relatively limited number of original forms-but not necessarily simple forms-all the other forms had developed through degeneration or hybridization. I do not intend to dwell on Lacepede's views here. What I wish to point out is that while Lamarck's views on species mutability seem to have been a natural outgrowth of his reluctance to admit species extinction, the particular form that his idea of evolution took reflected other ideas as well-ideas which he did not share with La- cepede or Buffon. Primarily these were his ideas on the origin and nature of life and on the natural arrangement of nature's productions.

Lamarck's ideas on the origin and nature of life changed markedly in the 1790s. In 1794 he maintained that what constitutes the essence of life is "truly a principle forever incon- ceivable to man." He wrote: "All the properties of matter joined to all the possible circumstances and even to the activity spread throughout the universe could not produce a being provided with organic motion, capable of reproducing its kind, and subject to death."48 By 1797, however, Lamarck no longer regarded life as a mysterious principle: "Life, in the beings which are endowed with it, is nothing other than the movement which results in the parts of these beings from the execution of the functions of their essential organs (or the possibility of being in possession of this movement when it is

46. Buffon, "De la d6g6n6ration des animaux," Histoire naturelle, 14 (1766), 374.

47. I intend to discuss Lac6p6de's views at greater length elsewhere. His most important texts for this study are his introductory discourses to the second and third volumes of his Histoire naturelle des Poissons (Paris, 1800 and 1802).

48. Lamarck, Recherches sur les causes des principaux faits physiques, II, 213-214.

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suspended)."49 In 1797 Lamarck stated explicitly that he did not consider the essence of life in a body to reside in a particular being or soul which vivified that body. The religious issue was one that he felt perfectly justified in skirting, for neither "man's immortal soul" nor "the perishable soul of beasts" could be known physically.50 He was still, however, a significant step away from the view he was to hold three years later.

In 1797 Lamarck presented nature on the one hand and the "power of life" on the other as two opposing forces-one de- stroying and the other renewing and building. He saw the dynamic interaction of these two forces as the cause of all the combinations of matter in existence.51 Between the beings of the animate and inanimate kingdoms, he observed, "there is, in a way, an infinite distance."' 52 Life, he supposed, is always the product of life: "It has been rightly said that everything that has life comes from an egg." 53 It was not until 1800 that he expressed a belief in spontaneous generation.

The critical change in Lamarck's thinking on the onrgin of life evidently occurred between 1799 and 1800. Lamarck is not explicit on how it happened, but I think a plausible explanation is within reach. Lamarck maintained that if one really wants to know what constitutes the essence of life, one must examine the simplest beings in which the phenomena of life exhibit themselves. He looked upon the least complex of the known animals as "nothing but a point which is gelatinous and transparent, but contractile." 54 This mechanical way of considering the simplest forms of life enabled an idea to come to him which he says, when it came, was like a "flash of light.",5 It occurred to him that the "excitatory cause of organic movement" in these simplest creatures and the "sole cause of their conservation" had to be external to them. Bot- anist turned zoologist, he had been naturally led to reflect upon

49. Lamarck, Mdmoires de physique et d'histoire naturelle, p. 255. The development of Lamarck's thinking on the nature of life may well have been influenced by his consideration of Spallanzani's observations on the reanimation of dessicated rotifers. See Lamarck, Systeme des animaux sans vert0bres, p. 387; Spallanzani, Opuscules de physique, animale et vdg6tale, 3 vols. (Pavia: 1787), II, 203-249.

50. Lamarck, M6moires de physique et d'histoire naturelle, p. 255. 51. Ibid., pp. 238-367 (see esp. p. 249). 52. Ibid., p. 246. 53. Ibid., p. 272. 54. Lamarck, Philosophie zoologique, I, 285. See also Syst#me des

animaux sans vert6bres, pp. 390, 397. 55. Lamarck, Philosophie zoologique, I, xvi.

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RICHARD W. BURKHAEDT, JR.

the similarities and differences between the plants and animals (a topic which had indeed interested him for some time). In 1797 he was maintaining that life in plants was "an activity provoked by an extemal cause." 56 Within a few years he came to a similar conclusion regarding the simplest animals. The external stimruli that he supposed to be operating were subtle fluids-caloric and electricity most likely. Viewing life as an organic movement, and viewing the subtle fluids as capable of stimulating motion in the ponderable fluids of the simplest creatures, Lamarck's further insight was that the very simplest of animals, the creatures which he referred to as "mere sketches of animality," could be formed when conditions were favorable, and destroyed when conditions were unfavorable.57 That he had not come to this conclusion in 1799 is evidenced by his opening discours of that year, in which he made the following statement conceming the simplest sorts of animals:

The waters are populated in a way with animated molecules which are endowed with organs as perfect for assuring their existence as are those of the largest animals, although the organization of the latter is more complex. Also these a ted molecules reproduce themselves as constantly and even with a facility and swiftness that is much superior. One can be sure that they hold in nature a rank that is no more uncertain, though in general it is less well known.58

Lamarck's Mbmoires de physique et dhistoire naturelle of 1797 and some manuscript notes for his opening discours of 1798 and 1799 indicate that in those years he was pondering the problem of generation. His interest in both plant and animal physiology had led him to consider the mechanisms of phenomena such as fertilization, germination, and incubation. Fertilization, he had come to believe, "is nothing other than an act which establishes a particular disposition in the interior parts of the gelatinous body that is fertilized-a disposition without which the individual would never be able to receive and enjoy life."59 It was just a step more to believe that, as he put it in 1802, "nature herself imitates her process of fer-

56. Lamarck, Mcmoires de physique et d'histoiTe naturelle, p. 279. 57. Lamarck, Systdme des animaux sans verthbres, pp. 41, 358-359. 58. Lamarck, "Discours de l'an VII," p. 3. 59. Lamarck, 'Toour mes legons. Histoire naturelle des animaux in-

vertibr6s ou A sang blanc. Discours prlirminaire. an VI A an VII," Mus6um national d'histoire naturelle, MS 2628 (1), p. 1. The same quote appears in Lamarck, Recherches sur l'organisation des corps vivans (Paris: 1802), p. 95.

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tilization in another state of things, without having need of the concourse or products of any pre-existant organization": 60

Why should not heat and electricity-which in certain countries and certain seasons are spread abundantly throughout nature, especially at the surface of the globe themselves operate on certain materials which come together in certain circumstances what the subtle vapor of fertilizing materials exercises on the embryos that it organizes and makes suit- able for life? 61

My guess is that Lamarck was led to the above conclusion through the consideration of the nature of the simplest forms of life and the problem of extinction as it applied to them. In 1800 he was indicating to his students the importance of beginning with an overview of "the vast ensemble of nature's productions." His thinking about the possibilities of extinction throughout much of the animal scale has already been discussed. But what about among the very simplest forms of life? What about the so-called monad, the sketch of animality which is but a gelatinous, contractile point? Here it was easy to conceive a mechanism of extinction-namely, the unexpected arrival of a "rigorous season."62 This was something which Lamarck as both a meteorologist and a Frenchman of the 1790's had no difficulty imagining. But how then was one to explain the reappearance of these simplest forms of life after a par- ticularly harsh period in which they all seemed to disappear? There was the problem. They seemed too frail to be able to withstand the adverse conditions themselves. Having no organs for sexual generation they obviously could produce no eggs. It was recognized that they reproduce instead through fission or budding. What was unknown to Lamarck was the encysted state in which they are able to survive adverse conditions. Not knowing this, he naturally concluded that instead of regener- ating themselves they were produced directly from inanimate matter when conditions were appropriate.63

Any explanation of the origin of Lamarck's belief in spontaneous generation must of necessity be somewhat speculative, but I believe that the explanation given here corresponds with what is known about Lamarck's thoughts on generation and on the simplest forms of life during the period in question.

60. Lamarck, Recherches sur l'organisation des corps vivans, p. 98. 61. Ibid., p. 101. 62. Ibid., p. 103. 63. Ibid., pp. 103-104. See also Systeme des animaux sans vertAbres, pp. 41, 391-392; and Philosophie zoologique, II, 83.

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Furthermore, it is strongly supported by the fact that from the outset Lamarck joined the idea that the simplest animals could be spontaneously generated under favorable conditions to the idea that the same animals could be destroyed completely when conditions were unfavorable. Simpson has por- trayed the function of spontaneous generation in Lamarck's system as the replenishment of the simplest forms of life as they move naturally up the evolutionary scale.84 This view suggests the possibility that it was Lamarck's broad view of evolution that initially forced him to postulate the occurrence of spontaneous generation. I believe, to the contrary, that La- marck first called upon spontaneous generation to account for the reappearance of forms that had been destroyed, not forms that had evolved, and that his belief in spontaneous generation was a precondition of his evolutionary theorizing rather than a deduction from it. Coming to believe in spontaneous generation was evidently a major watershed in his thinking. He himself was later to claim: "Once the difficult step [of admitting spontaneous generation] is made, no important obstacle stands in the way of our being able to recognize the origin and order of the different productions of nature." 65

Lamarck's new beliefs in species mutability and spontaneous generation were the two crucial additions to his thinking in the period 1799-1800. Though these ideas seem to have been directly related to his consideration of the question of extinction, it is evident that he seized them gladly not only in relation to the question of extinction but also because of their useful- ness to him in defending his old view on the natural way to arrange nature's productions, a view which his studies on the invertebrates seemed to him to be confirming nicely.68

The idea that within each of nature's kingdoms nature's productions could be arranged linearly according to complexity of organization was, in the words of Daudin, "the active formula of [Lamarck's] thought in natural history" throughout the course of his career.67 In the latter half of the 1790's, thanks primarily to Cuvier's anatomical researches,68 Lamarck was

64. George Gaylord Simpson, This View of Life (New York, 1964), p. 46. 65. Lamarck, Recherches sur l'organisation des corps vivans, pp. 121-

122. See also Histoire naturelle des animaux sans vertabres, I (Paris: 1815), 180-181.

66. Lamarck refers to implicit attacks on the linear arrangement of organisms in SystOme des animaux sans vertabres, p. 17 n.

67. Daudin, CUVier et Lamarck, II, 155. 68. Cuvier, "M6moire sur la structure intemne et externe, et sur les

affinit6s des animaux auxquels on a donn6 le nom de vers; lu A la SociOt6

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finding the major divisions of animals amenable to this kind of linear arrangement, and the invertebrates, as he put it in 1800, "show us even better than the others this surprising degradation in the composition of organization."69 There is, however, no compelling reason to suppose that merely contem- plating this new evidence of the degradation of organization within the animal scale was enough to convince him of evolution. Chronological evidence suggests that this was not the case, for Lamarck had incorporated Cuvier's observations into his own thinking as early as the spring of 1796.70 In addition to being struck by the gradation of complexity throughout the animal scale, he still had to come to believe in spontaneous generation, and that evidently occurred after he delivered his introductory discours of 1799. As of 1800, he felt that he had an explanation of why the different classes of animals should conform to a linear scale of increasing complexity and why at the same time many species and some genera could not be fitted into this general scheme. The general series of increasing complexity, he was able to claim, was by no means artificial. It represented the actual course nature had followed in pro- ducing the various classes of living things. As he put it in a little-known work published in 1803:

This real gradation in the organization of living things must necessarily be regarded as the result of nature's true way of proceeding [marchel. In truth, it is very little evident in the plants, while in the animals, it displays itself in an eminent manner; but it exists no less in the former than in the latter, and the better known the organization of these beings becomes, the more the necessity of distributing the orders which divide them according to nature's way of proceeding will be felt.7'

Significantly enough, as we have already seen, Lamarck in 1800 was claiming that he could show that all the parts, organs, and faculties of every class, order, genus, or species were the result of the particular circumstances to which the races of each species had been subjected by nature. Though he repeated this claim in 1802, his thinking by then had evidently de-

d'Histoire naturelle, le 21 flor6al de I'an 3 [10 May, 17951 La D6cade philosophique, litt6raire, et politique, 5 (1795), 385-396.

69. Lamarck, Systeme des animaux sans vertebres, p. 11. 70. "Nouvelles litteraires," Mag. encyc., 2? annke (1796), I, 285. 71. Lamarck, Histoire naturelle des v6getaux, 2 vols. (Pads, 1803), II,

257-258.

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RICHARD W. BUTRKHARDT, JR.

veloped a step further. He maintained then and thereafter that the basic features deternining the general animal series were the result of the tendency of "organic movement" in living things to make their organization increasingly complex.72 The particular circumstances to which living things had been subjected were responsible for the lateral ramifications from the general series-ramifications formed by certain species and genera. His evolutionary theory had taken its essential shape.

In 1815 in his Histoire naturelle des animaux sans vert&- bres Lamarck claimed that, in regard to the source of "the existence, the manner of being, the faculties, the variations, and the phenomena of organization of the different animals," he had presented "a truly general theory, linked everywhere in its parts, always consistent in its principles, and applicable to all the known data."73 It is not my purpose here to judge whether Lamarck's theory was as well integrated and compre- hensive as he claimed. That deserves a full study in itself. I would point out, however, that it is possible to view Lamarck's writings after 1802 as containing not just one theory of organic change but two. One explains the broad patterns of organic diversity-the shape of the evolutionary tree, so to speak. In this explanation the "pouvoir de la vie," or tendency toward increased complexity, is the doMinant factor. Environmental influences are responsible only for the departures from the general scale. When Lamarck sets out to explain how it is that particular individuals or species actually change, however, he generally neglects the pouvoir de la vie, maintaining that a species will remain unchanged as long as the environment in which it exists remains unchanged.74 It may be argued that these were but two levels of explanation within a single well- integrated theory, and this is presumably the way Lamarck viewed the matter (if he considered it at all). The ways in which Lamarck's ideas have been misrepresented by followers and detractors alike would suggest, however, that his theory can be broken apart with relative ease. I believe that a certain dichotomy existed in Lamarck's evolutionary thinking from the beginning. His general theory of evolution was not simply extrapolated from his idea of species mutability, but neither

72. Lamarck, Recherches sur l'organisation des corps vivans, pp. 7-8. The statement of 1800 is repeated on p. 62.

73. Lamarck, Histoire naturelle des animaux sans vertAbres, I, iii-iv. 74. See, for example, Lamarck, "Esp6ce," Nouveau dictionnaire d'histoire

naturelle, 10 (1817), 448-450. For Lamarck's inconsistency on this point, compare in Philosophie zoologique, p. 70 with pp. 132-133.

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was his concept of species mutability simply deduced from the idea that all living things must be truly the productions of nature.

I would like to conclude with an observation on Lamarck's two-factor explanation of organic diversity. While this was a novel explanation, it represented a model of development that was familiar to the eighteenth century not only in certain sciences but also in the writing of a certain kind of history. Indeed, Lamarck's evolutionary theory may be seen as a natural history in the same sense in which that term applies to Rous- seau's Discourse on the Origin of Inequality, to Adam Smith's Wealth of Nations, to Hume's Natural History of Religion, and to Malthus' Essay on the Principle of Population.75 In each of these works, regardless of the particular focus, one is told what the natural course of events would be were it not for constraining circumstances. As Dugald Stewart observed in discussing what he called "theoretical" or "conjectural" history:

In most cases it is of more importance to ascertain the progress that is most simple, than the progress that is most agreeable to fact; for, paradoxical as the proposition may appear, it is certainly true that the real progress is not always the most natural. It may have been determined by particular accidents, which are not likely to occur again, and which cannot be considered as forming any part of that general provision which nature has made for the improve- ment of the human race.76 The parallel with Lamarck's two-factor theory should be ob-

vious. My purpose, however, is not merely to point out the uses of this model of explanation in the eighteenth century. It is my opinion that various historical treatments of the origin of Lamarck's belief in evolution in effect correspond to this model. The writers who have advanced these explanations have accepted too simple or too natural a reconstruction of La- marck's intellectual development. Lamarck's own description of the origin of his views strikes me as the way things might ideally have happened rather than the way they probably happened in fact, and I would apply the same criticism to certain more recent explanations as well.

75. The kind of history represented by the four works mentioned has been discussed by Frederick J. Teggart, Theory of History (New Haven: 1925), chap. 8. See also Robert A. Nisbet, Social Change and History (London, Oxford, New York, 1969), pp. 139-158, who follows Teggart's lead.

76. Dugald Stewart, "Account of the Life and Writings of Adam Smith," cited in Nisbet, Social Change and History, p. 157.

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My conclusions from my own study of Lamarck are that the broad foundations on which his biological and evolutionary thought rested were developed rather early in his career, and that these early foundations largely determined the nature of the theory he eventually developed. His early thoughts on the natural way to arrange nature's productions were decisively reflected in his evolutionary theory. His physiological views contributed to his assessment of the mechanisms of organic change. His physico-chemical views, which he never really re- nounced in the 1800's, found a place in his evolutionary theory in the action of subtle fluids on ponderable fluids, and through these on organic forms.77 Geological views that he shared with a number of his contemporaries also played a crucial role in his theorizing. Had it not been for the particular questions he confronted in the period 1799-1800, however, it is not clear that he would ever have constructed a theory of evolution at all. The immediate inspiration of Lamarck's belief in evolution came from his studies in invertebrate zoology: from the issue of extinction which his conchological studies posed dramati- cally to him, and from the thoughts on the origin of life to which his ideas on the structures of the simplest animals inevitably led him.

77. In regard to the influence of Lamarck's physico-chemical views on his evolutionary thought, I do not agree with Gillispie that "What [Lamarck] did between 1797 and 1800 was to assimilate the question of organic species (or rather of their nonexistence) to that of species in general, and of mineral species in particular" (Gillispie, "The Formation of Lamarck's Evolutionary Theory," p. 329). Gillispie's explanation fails to recognize the fundamental distinction that Lamarck, like his colleague Daubenton, characteristically made between mineral "sortes" and organic "esp&ces." Hodge, though offering an explanation different from Gillispie's, also fails to make this important distinction (Hodge, "Lamarck's Science of Living Bodies," pp. 333-334).

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