Alpheus Spring Packard and cave fauna in the evolution debate

Alpheus Spring Packard and Cave Fauna in the Evolution Debate

STEPHEN BOCKING

Institute for the History and Philosophy of Science and Technology University of Toronto Toronto, Ontario

The publication in 1859 of The Origin of Species led to the eventual acceptance of the fact of evolution by the American scientific community. Yet the perceived inadequacy of Darwin’s mechanism of natural selection led many American naturalists to search for an alternative, and many adopted neo-Lamarckism as a superior explanation of the observed phenomena of paleontology or natural history.

A key difference between these two theories is that neo- Lamarckism attaches more evolutionary significance to interac- tions between an organism and its physical environment, while Darwinism sees greater significance in the competition between organisms. Cave fauna, displaying bizarre adaptations to an extreme environment, were interpreted by neo-Lamarckians as providing excellent evidence for the effect of the environment upon the evolution of organisms.

Alpheus Spring Packard was a leading American researcher in cave biology in the last half of the nineteenth century. He had become a Lamarckian before he took up the study of cave fauna. This work, however, convinced him that the physical environment was the primary factor modifying organisms, and was capable of inducing extremely rapid evolution. His new awareness of the power of Lamarckian factors led him to become the leading promoter of the theory among American neo-Lamarckians, and a firm opponent of the neo-Darwinians. Because the phenomenon of the adaptation of cave fauna was especially suited to the views he wanted to promote, he devoted much effort throughout his career to cave study. Although, according to Packard, the course of evolution was dependent on environmental factors, he also maintained that the history of life indicated the presence of underlying progressive trends, as recorded in the ontogenetic development of each organism. His theory reflects the great influence of his teacher, Louis Agassiz, and the need to reconcile his science with his strong religious beliefs.

Journal of the History of Biology, Vol. 21, No. 3 (Fall 1988), pp. 425-456 0 1988 6y Kluwer Academic Publishers.

426 STEPHEN BOCKING

EVOLUTION IN AMERICA

Edward Drinker Cope and Alpheus Hyatt were the first American scientists to prepare a significant alternative to Darwin’s theory of evolution by natural selection. Both of these scientists were colleagues of Packard - Hyatt from the early 186Os, when they were both students under Agassiz, and Cope from 1879, when he joined Packard as editor of the American Naturalist. Their influence is conspicuous in Packard’s preliminary speculations on evolution, and they led him to adopt neo-Lamarckism, which dominated evolutionary theory in America until the end of the century. Cope and Hyatt promoted different forms of neo- Lamarckism: Hyatt, in his studies of cephalopods, emphasized orthogenetic evolutionary trends, whereas Cope argued that the inheritance of acquired characters is the basis of evolution.

Hyatt published in 1866 the first significant paper of American neo-Lamarckism, “On the Parallelism between the Different Stages of Life in the Individual and Those in the Entire Group of the Molluscous Order Tetrabranchiata,” based on his study of the collection of ammonites in the Museum of Comparative Zoology at Cambridge. No mention was made of a Lamarckian mechanism, but the concept of acceleration, to which Packard later referred, was used to explain how “the life of the individual, so far as the shell and its internal structure indicate what its metamorphoses were, displays during its rise and decline, phenomena correlative with the rise and decline of the collective life of the group to which it immediately belongs.” ’ In its youth, a lineage would advance by the addition to its ontogeny of the youthful stages of its phylogeny. After the lineage had achieved its greatest potential, it would begin to decline, as the senile stages of its phylogeny were added onto the ontogeny of each individual. The inevitable end of each lineage, as of the individual, is extinction. The accumulating stages in ontogeny would be accommodated in a finite life span by the acceleration of the development of each stage.’ Hyatt eventually accepted that the influence of the environment could control the addition of new stages to an organism’s ontogeny. This mechanism, however, remained secondary to the underlying trend

1, Alpheus Hyatt, “On the Parallelism between the Different Stages of Life in the Individual and Those in the Entire Group of the Molluscan Order Tetrbranchiata,” Mem. Roston SOC. Not. H&t., 1 (1 866), 193.

2. Stephen J. Gould, Otztogerzy ~/IL/ /‘lq$oger~~ (Cambridge; Mass.: Belknap Press of Harvard University Press, I Y77), pp. Y I -Y6.

Alpheus Spring Packard and Cave Fauna 427

toward racial senility.” Hyatt owed much to his teacher Louis Agassiz; his law of acceleration, as he noted, was a direct descen- dant of Agassiz’s principle of recapitulation.J

Cope also owed much to Agassiz’s principle; however, his theory of evolution by acceleration and retardation differed in several respects from Hyatt’s theory. Cope had expressed his dissatisfaction with natural selection as early as 1864, but he did not propose an alternative until 1866.5 In 1868 he attempted to generalize his theory for the entire animal kingdom: The addition of a new stage onto the life history of each individual of a species occurred very abruptly, between periods of developmental stabil- ity; each such transition would propel the species into a new genus. Cope, unlike Hyatt, did not account for the correspondence of the decline of a lineage to an individual’s ontogeny by the addition of “old-age” stages. Rather, in this period of the phylogeny stages began to be dropped from ontogeny, as a result of the “retardation” of development. This process would eventually lead to the extinction of the lineage. Like Hyatt, Cope made no mention in this paper of Lamarck or of the inheritance of acquired characteristics. Three years later, in 1871, in “The Laws of Organic Development,” he supplemented acceleration and retardation with other factors more reminiscent of those invoked by Lamarck - but he still did not mention Lamarck.6 Acceleration and retardation were only responsible for change during the period that the organism was actually growing. Beyond this time, evolution would be guided by the factors that guided the “growth force” which regulated the amount of growth of each part of the body; these

3. Peter Bowler. The Edipsr of Drrrwinism (Baltimore: Johns Hopkins

University Press, 1983) p. 127.

4. Alpheus Hyatt, “Cycle in the Life of the Individual (Ontogeny) and in the Evolution of its Own Group (Phylogeny).” I’KX Amer. Atnd Ails Sci.. .?? (lXY7),217.

5. Edward D. Cope, “On the Cyprinidae of Pennsylvania.” Tvrrns. Amcu. Phil. sot., 13 (1 X66). 3Y7-3YY.

6. Edward D. Cope, “The Laws of Organic Development,” Atnrr. Nur., -5

(1871), 593-605. Cope, in an additional paper published the same year, took pains to emphasize that he had not been influenced by Lamarck. however similar their ideas were: “There will probably be found considerable resemblance and

coincidence between the theory of use and effort. and the Lamarckian view of development. The writer has never read Lamarck in french, or seen a statement of his theory in english. except the very slight notice in the origin of Species and Chamber’s Encyclopaedia, the latter subsequent to the first reading of this paper”

(Edward D. Cope, “The Method of Creation of Organic Forms,” I’roc. Amer. I’hii. Soil., I2 [I x7 I I. 362.

428 STEPHEN BOCKING

included one minor factor - physical and chemical causes - and two major factors - use and effort.

Neo-Lamarckism spread quickly after Hyatt and Cope published the ideas described above. As their work shows, neo- Lamarckism was not originally based on what is considered today to be its distinguishing feature: a belief in the heritability of acquired characters as the dominant creative force of evolution. Early neo-Lamarckism was significant because of its status as a self-conscious alternative to Darwinism and because of the research it encouraged in comparative embryology and paleontology, rather than because of the durability of its ideas of deter- ministic evolution.

Packard did not distinguish between the theories of Cope and Hyatt; in his opinion, “Hyatt’s views essentially agreed with those published by Cope, but were less genera1 in their application.“’ His studies .of cave fauna emphasized the inheritance of acquired characteristics, but Packard did not contradict Hyatt’s emphasis on overall trends in evolution, although he rejected his pessimistic views on the inevitability of racial senility. Cave fauna could demonstrate the power of the physical environment as an evolutionary factor, capable of maintaining an organism’s adaptation to its changing surroundings. Packard attributed more evolutionary importance to the direct effect of the environment than to the effect of changes in habits. Cave research therefore helped to established that the changing environment could be responsible for the underlying progressive trends in evolution that Packard demonstrated in his work in embryology.

RESEARCH INTO CAVE FAUNA

The blind fauna inhabiting North American caves had been cited in discussions of the origin of species and the effect of the environment on organisms almost since the time they were first described in 1842. The Mammoth Cave of Kentucky, the largest and most famous cave in the United States, was the first to supply a specimen of an eyeless fish and an eyeless crayfish, brief descriptions of which were published in 1842.b: Later in the same year, James De Kay of New York published in his Zoology oflvew York a description of a blind fish obtained from the cabinet of the

7. Alpheus S. Packard, “A Century’s Progress in American Zoology,” Amer. Nar., IO (1873 597.

8. W. T. Craige, “[Mammoth Cave Blind Crayfish and Fish],” Prof. Acad. Nat. Sci. Phila., I (1842), 175.


Lyceum of Natural History of New York. He considered it sufficiently novel to warrant a new genus and species designation, naming it Arnblyopsis spdoeus, and he thought it “probable that it may form the type of a new family of the soft-rayed abdominal forms.“’ These descriptions caused a brief flurry of interest; within the next two years several more detailed descriptions of the blind fauna of the Mammoth Cave were published by William Thompson, “I Jeffries Wyman, t’ Theodor G. Tellkampf,” and David Humphreys Storer.‘”

Tellkampf contributed detailed descriptions of the blind fish of the cave, and named and described a large number of new species of cave fauna. He concluded that the eyes of Amblyopsis and the blind crayfish had become rudimentary as a result of disuse: “While it is true, in general, that all animals retain their essential form, and that no species passes over into another by transformation, we know that less material changes of form are produced by external influences such as changes of climate or food, lasting through many generations of the same species.” ” But if the lack of light could only produce change within a species, then where were the original unmodified species? Tellkampf remained cautious on this point: the relationship of the blind fauna to unmodified species could not be settled until “such species, corresponding with them in all essential points, are found.” I5

Wyman also contributed a series of studies of the anatomy of a blind fish that agreed, for the most part, with the Amblyopsis speloeus described by De Kay. In his first paper, he reported that on “the most careful dissection no traces of eyes were found.“‘” Seven years later, in 1850, Wyman described his discovery of the optic lobes in the blind fish. Their presence, in the absence of the other organs of vision usually associated with the lobe, made him wonder if “these lobes are the seat of any other function than that

9. James De Kay, Zoology of New York, or the New York Fauna (Albany: W. &A. White &J. Visscher, 1842) Part IV, Fishes, 187-188.

10. William Thompson, “Notice of the Blind Fish, Crayfish, and Insects from the Mammoth Cave. Kentucky,” Ann. Mq. Nat. Hist.. 13 (1844), I 1 1.

1 1. Jeffries Wyman, “Description of a ‘Blind Fish’ from a Cave in Kentucky,” AWI. Mq. Not. H&-t., 12 (1 X43). 298-29’3.

12. Theodar G. Tellkampf, “Memoirs on the Blind-fishes and Some Other Animals Living in the Mammoth Cave in Kentucky,” N. Y. J. Med.. July I X45, x4--93.

13. David H. Storer, Synopsis of the Fishes of North America (Cambridge: Amer. Acad. Arts & Sciences, 1846).

14. Tellkampf, “Memoirs,” pp. 92-93. IS. Ibid.. p, 93. 16. Wyman, “Description.” p. 2YY.

430 STEPHEN BOCKING

of sight.” ” In 1854, stimulated by reports from others of observations of black eye dots visible on A. spefoems, he reexamined three specimens and found imperfect eyes, covered by areolar tissue and skin, and hence unable to see. Ii: He proposed that this imperfec- tion of the eyes “might be owing to a want of stimulus through a series of generations.” r4)

Louis Agassiz emphasized in 185 1 the potential significance of the cave fauna: “You asked me to give my opinion, respecting the primitive state of the eyeless animals of the Mammoth Cave. This is one of the most important questions to settle in natural history, and I have several years ago, proposed a plan for its investigation, which, if well conducted would lead to as important results, for it might settle, once for ever, the question, in what condition and where the animals now living on the earth, were first called into existence.” 2’1 In the next paragraph, he suggested that cave animals could easily be used to ascertain whether “physical circumstances ever modified organized beings.” He argued therefore that examination of the cave fauna could contribute to the solution of two problems: the origin of animals, and the effect of the environment on animals. Agassiz’s discussion hints at what became the two roles of cave fauna in the development of evolutionary theory: as evidence for the fact of evolution itself, and as evidence for the action of a particular mechanism of evolution. Agassiz attempted to inspire young scientists to devote themselves to solving the puzzle of the origin of cave fauna: “Whoever would settle the question by direct experiment might be sure to earn the everlasting gratitude of men of science, and here is a great aim for the young American naturalist who would not shrink from the idea of devoting his life to the solution of one great question.“*’ He recommended a comparative anatomical study of the cave species and allied surface species, followed by embryological study of these species, and the raising of the young of cave species under varying conditions. No American naturalist heeded Agassiz’s call to begin these investigations.

17. Jeffries Wyman, “On the Blind Fish of the Mammoth Cave,” Proc. Boston Sot. Nat. Hist., 3 (1850), 349.

18. Jeffries Wyman, “On the Eye and the Organ of Hearing in the Blind- fishes (Amblyopsis speloeus) of the Mammoth Cave,” Proc. Boston Sot. Nat. Hist., 4 (1854), 395-397; 5 (1854), 18-l 9.

19. Ibid., p. 397. 20. Louis Agassiz, “Observations on the Blind Fish of the Mammoth Cave,”

Amer..I. Sci., 62 (1851), 127-128. 21. Ibid.,p. 128.


Charles Darwin used the observations made by the Danish naturalist Jorgen C. Schiodte of European cave animals, and the observations of James Dwight Dana of American cave fauna as explicit support for evolution. Noting that cave fauna, like the fauna of other isolated habitats, are more closely related to the fauna of the surrounding region than elsewhere, he argued that the cave fauna had descended from the fauna of the surrounding region, “the colonists having been subsequently modified and better fitted to their new homes.“”

Darwin at first considered both natural selection and disuse to be the factors producing the adaptations of cave fauna. Some cave fauna exhibited no traces of eyes, while the eyes of others were greatly enlarged. To Darwin, this suggested a “contest . . . between selection enlarging and disuse alone reducing these organs.“‘” He attributed other adaptations to cave life, such as elongated appendages, to selection. Darwin’s discussion of cave fauna did not change significantly between his draft long version (1856) and the first edition of The Origin of Species (1859). In the third edition of the Origin (1861), however, he deemphasized the importance of natural selection, eliminating the speculation of a “contest” between selection and disuse.‘J

In 1864 Cope examined two specimens of a blind siluroid, or catfish. Each had eyes that differed in degree of development, those on the left side being more rudimentary than those on the right. For Cope this had implications for the mechanism of evolution recently proposed by Darwin. In Cope’s view, these fish were a transitional form between two genera, involving the modification of the eyes, organs of “physiological and systematic significance”; because the significance of this generic modification is apparent, the problem experienced by natural selectionists of explaining the structure as a “step in the advance towards, or in the recession from, any utlktzown modification needful to the

22. Charles Darwin. Tllr Origit7 ufS,uecie~ (London: John Murray, 1X.59) p. 103.

23. Charles Darwin, Nc7trrrcrl Selection. ed. R. C. Stauffer (Cambridge: Cambridge University Press. 1975). p. 296.

24. Darwin also responded in the third edition of the Origin to Andrew Murray’s claim that the presence of cogeneric cave insects in widely separated caves. and the absence of the genus outside the caves, indicates the separate creation of these insect species. Darwin was surprised he had not thought of this difficulty. but he considered the phenomenon easily explained: the cave fauna were the only surviving members of that genus, having been protected from competition and extermination (Life trnd Letters of C’l7urks fhrnin, ed. Francis Darwin [New York: Appleton, 18971. II. 264-266).

432 STEPHEN BOCKING

existence of the species,” is avoided.” It was impossible, according to Cope, to show how the modification could have been gradually produced, as would be required by a selectionist explanation. He did not, of course, provide until 1866 an alternative mechanism for this generic modification.

Hyatt visited Mammoth Cave in September 1859 and collected specimens, before Cope or Packard had ever encountered cave fauna - but he did not use these specimens as the basis for evolutionary speculations.

For twenty years there was no serious attempt to follow Agassiz’s call to “settle the question” of the origin of cave fauna. Tellkampf and Wyman had speculated cautiously on the effects of disuse, and Cope had used the example of a cave fish to indicate his dissatisfaction with natural selection. No one undertook the detailed embryological analysis and experimentation that Agassiz suggested would be necessary to settle the question. The field remained open in 187 1 when Packard began his study of cave life.

PACKARD

Alpheus Spring Packard (1839-l 905) was an entomologist and naturalist of wide-ranging interests. While growing up in Maine and attending Bowdoin College, he studied most areas of natural history, but by 1860 he had developed a special interest in entomology. In 1861 he began study in entomology at the Lawrence Scientific School under Louis Agassiz. From 1862 until 1864 he was an assistant under Agassiz in the Museum of Comparative Zoology. Other assistants in the museum at the time included Hyatt, Frederick Ward Putnam, and Addison Verrill, each of whom maintained professional ties with Packard for many years.“’ Packard then worked for a variety of educational institu- tions and government agencies; these included the Geological Survey of Kentucky in 1874 when he surveyed the Mammoth Cave and neighboring caves,27 and the United States Geological and Geographical Survey of the Territories in 1875-1876, when he explored Clinton’s Cave in Utah.28

25. Edward D. Cope, “On a Blind Silurid, from Pennsylvania.” Proc. Actrd. Nut. Sci. Phila., 16 (I X61), 232.

26. T. D. A. Cockerell. “Biographical Memoir of Alpheus Spring Packard I83Y- I YOS,” Hog, Mem. Ncrt. Acrid. SC, Y (I 920). 192.

27. Alpheus S. Packard;‘The Cave Fauna of North America, with Remarks on the Anatomy of the Brain and Origin of the Blind Species.” Mrm. Not. Aurti. Sci., Y (I X88). 3.

2X. Ihid.. p. 1’9.


In 1878 Packard was appointed Professor of Zoology and Geology at Brown University, where he remained until his death. Apart from his studies of cave fauna, he was noted for his work in taxonomic and applied entomology, and for his studies in the embryology of the invertebrates. A leader between 1870 and 1900 of American neo-Lamarckians, he was among them the most aware of their intellectual inheritance from Lamarck. This awareness led him to coin the term “neo-Lamarckism,” and to write a biography and analysis of Lamarck and his writings, which he published in 190 1 .3g In this work he championed Lamarck as the “real founder of organic evolution,““’ and he did not hesitate to emphasize that he had long been influenced by him: “The name of Lamarck has been familiar to me from my youth up . . . for over thirty years the Lamarckian factors of evolution have seemed to me to afford the foundation on which natural selection rests, to be the primary and efficient causes of organic change, and thus to account for the origin of variations, which Darwin himself assumed as the starting point or basis of his selection theory.““’

Although Packard emphasized that Lamarck was known to him almost from boyhood, his earliest theoretical papers exhibit more of Agassiz’s influence. His early work on insects dealt with their morphological development, and the bearing that such observations have on their classification. In a paper published in 1863 he attempted to show that the insect order Neuroptera is a “synthetic type,” in that it combines characters found in the two series of insect orders that culminate in the Hymenoptera and the Coleoptera. Thus, Packard hoped to “reunite this seeming polarity” among insects, as Agassiz, under whom he was studying at the time, had done with fish: Agassiz had argued that the class of Selachi “combine the characters of all the other classes of fishes existing during the same period.“3’ This early example of Packard’s work demonstrates Agassiz’s influence, both in his attempt to emulate Agassiz’s work in classification, and in the lack of any evolutionary perspective in the discussion.

Packard’s work in the 1860s continued to reflect the influence of pre-Darwinian theory. In papers on the classification and morphology of insects published in 1866 and 1867 he retained a nonevolutionary perspective. In a paper on the Hymenoptera, he

29. Alpheus S. Packard, Larnarck, the Founder of El:olLrtion, His Life and Work (New York: Longmans, Green, 190 1).

30. Ibid.. p. v. 3 1. Ibid.. p. viii. 12. Alpheus S. Packard, “On Synthetic Types in Insects,” Boston J. Nat. Hist.,

7 (I 863), 593.

434 STEPHEN BOCKING

revised the scheme he had set out in his 1863 paper, in which the Coleoptera and Hymenoptera were each the culmination of a series of insect orders; now, he described the Hymenoptera as the “most perfectly organized,” and the culmination of a series comprising all insects. Following J. D. Dana’s theory of classification by cephalization3” the characteristic that made Hymenoptera the most advanced insect order was the “throwing fovwavds [of] the prime elements of the organism, by which it becomes more cephalized, and thus the nervous power rendered more centralized than in all other articulates.““4

A second important aspect of Packard’s nonevolutionary work was the principle of the ideal type. His discussion of the classification of the worms, crustacea, and insects within Cuvier’s embvanchement, the Articulates, applied the principle that every form could be reduced to a “simple, ideal, typical figure; that of a long slender cylinder divided into numerous segments.“3’ Accord- ing to Packard, insects are the “completion and final development of the articulate plan,” which was only hinted at by the classes at lower positions on the “scale of being” of that type.“” He accepted the extension of the concept of ideal types beyond the Articulates: “in the animal kingdom as a whole . . . there is a deeper-seated tendency of all young organisms towards a perfection of the type to which they belong.“j7 Packard clearly received this principle from his former teacher, Agassiz, who had argued in his “Essay on Classification” that “the identity of structure among animals does not extend to all the four branches of the animal kingdom; that, on the contrary, every great type is constructed upon a distinct

33. Dana’s principle of cephalization was a method of ranking organisms, as an aid to classification. Dana considered it a “fundamental principle, as respects grade, in zoological life” (James D. Dana, “On the Higher Subdivisions in the Classification of Mammals,” Amer. J. Sci., 35 [1863], 65). The principle called for the separation of each animal body into an anterior, or cephalic, portion, which includes the head and the organs anterior to the organs of locomotion, and a posterior portion, which is the rest of the body. The rank of an organism was simply based, then, on the principle that “concentration of the anterior extremity of the body and abbreviation of its posterior portion is a mark of elevation” (James D. Dana, “The Classification of Animals Based on the Principle of Cephalization,” Amer. J. Sci., 36 [ 18631, 321; Dana, “Classification of Mammals,” p. 66).

34. Alpheus S. Packard, “Observations on the Development and Position of the Hymenoptera, with Notes on the Morphology of Insects,” Proc. Boston Sot. Nat. Hist., 10 (1866), 291.

35. Alpheus S. Packard, “Insects and Their Allies,” Amer. Nut., f (1867) 73. 36. Ibid., p. 77. 37. Alpheus S. Packard, “On Certain Entomological Speculations - A

Review,” Proc. Entomol. Sot. Phila., 6 (1864) 207-249.


plan.” js Through Agassiz, Packard’s intellectual inheritance reached back to those who had most influenced Agassiz, and particularily to Ignatius Dollinger, Karl Ernst von Baer, and Georges Cuvier.

By 1867 both Cope and Hyatt had proposed their schemes of evolution by acceleration and retardation. Yet Packard’s religious convictions prevented him from accepting a theory that did not, in his view, provide a full explanation of the origin of life: “The theories now in vogue, suggested by Lamarck and Darwin, or as modified by other naturalists, though so stimulating to scientific thought, are yet not satisfactory, and do not go to the bottom of the matter. We must still wait patiently, and meanwhile observe, experiment, and reflect, and thus continue to question nature until she yields a willing reply.“3’ Packard felt that a deeper explanation of, for example, the metamorphosis of the bee lay in the “plan of life originally marked out for the insect by the creative mind.““”

These early papers on the development and classification of insects, published between 1863 and 1867, were implicitly nonevolutionary. But by 1875 Packard’s studies of development had been thoroughly recast into an evolutionary Lamarckian mold.” It is not certain how Packard became a Lamarckian evolutionist. He described the event in his biography of Lamarck: “The present writer, from a study of the development and anatomy of Limulus [the horseshoe crab] and of Arthropod ancestry, was early (1870) led to adopt Lamarckian views in preference to the theory of Natural selection, which never seemed to him adequate or sufficiently comprehensive to explain the origin of variations.“42 However, as Peter Bowler points out, that paper on Limulrts only supported Cope and Hyatt’s law of acceleration.4” In it, Packard described the development of Limulus polyphemus: the embryo

38. Louis Agassiz, “Essay on Classification, ” in Contributions IO the Natural History of the United States, I (Boston: Little, Brown, 1857), 20.

3Y. Alpheus S. Packard, “Review of Lubbock: Development of Chloeon,” Amer. Nat., I (1867), 429.

40. Ibid. 41. Packard retained many of the concepts he had learned from Agassiz even

after he became an evolutionist. For example, that of the ideal insect type as the first insect form to appear: insects of increasing complexity gradually appeared through modifications of the ideal type, as progress was made in ascending the “scale of being.” He acknowledged, though, that irregularities exist: “this conti- nuity of improving organizations is often broken, and we often see insects which recall the earlier and more elementary forms” (Alpheus S. Packard, Our Common Insects [Salem, Mass.: Naturalists’ Agency, 18731, p. 15 1).

42. Packard, Larnarck, p. 390. 43. Bowler, Eclipse, p. 134.

436 STEPHEN BOCKING

begins as a nauplius, before adopting the form of a trilobite; from the trilobitic stage the larva passes through a “slightly marked metamorphosis” to attain the adult form.“4 Packard decided that a nauplius form was the common ancestor of Limdus and the other members of the order of Branchiopoda. He concluded that “the origin of these forms may be accounted for rather by a process of acceleration and retardation of development as suggested by Messrs. Cope and Hyatt, involving a more or less sudden formation of genetic forms, than by the theory of natural selection, which involves an indefinite number of slight modifications for the production of even a variety, and such a succession of inter- mediate generic forms as we do not perhaps find recent or fossil.“4”

Packard delivered this paper in August 1870 at the annual meeting of the American Association for the Advancement of Science, the proceedings of which were published the following year. His adoption of a Lamarckian mechanism appears not to have occurred in 1870, but in the following year, as a result of additional observations of Limulus. In a second paper, “The Development of Limulus polyphemus” - read before the Boston Society of Natural History on November 16, 1870, subsequently revised as a result of observations made during the summer of 1871, and then published in 1872 - Packard discussed how the embryology of Limuh illustrated the effect of physical factors:

I am strongly inclined to believe that the great differences in the egg, the development of the primitive disk, the singular amnion and the almost ametabolous young of Limulus, so unlike other Crustacea, are possibly due to the eggs being laid by the parents in the sand or mud between tides . . . . To withstand the action of the waves, the alternations of heat and cold, the chances of being even left for weeks and perhaps months on dry land, before an extra high tide can bear them back into the water, the yolk cells must be small and exceedingly numerous, so as to make the egg contents unusually compact, as they are in Limulus. . . . That the differences in the egg of Limulus from those of most other Crustacea are due to physical causes, and

44. Packard stated in a later paper that Limulus was a significant organism to study because of its status as an ally of the trilobites, and because it is “so unlike in its organization to the normal crustaceans” (Alpheus S. Packard, “Mode of Growth of the Lower Vertebrates,” Amer. Nat., 9 /1875), 589).

45. Alpheus S. Packard, “On the Embryology of Limulus polyphemus, ” Proc. Amer. Assoc. Adv. Pi., 19(1871), 255.


induced by them rather than correlated with them, is shown in the summer and winter eggs of the Cladocera, the long period of winter causing the eggs which are laid in the autumn to have an extra protection.“6

Thus Packard published two papers on the same subject within a short space of time, the first containing a vague discussion of “acceleration and retardation of development,” and the second explicitly stating that the characteristics of Limulus are due to physical causes. The only additional data that Packard had available for the second paper, but not for the first, were the observations made during the summer of 1871 - and the only observations that he explicitly states were made in 1871 concerned the ability of the eggs to survive for long periods of time: “In the succeeding summer (July 187 1) the hatching jar . . . contained several embryos in eggs laid during the preceding year, in different though advanced stages of development, and also several larvae hatched during 1870, though in a torpid state, due probably to the little air in the water. I much doubt whether the eggs of any other living crustacean would show as much vitality.““’

The observation that the eggs of Limulus are resistant to extreme conditions, together with the fact the eggs are often laid in harsher environments than the eggs of other Crustacea, may well have led Packard in 1871 to conclude that the extra protection given to Limulus eggs was due to the action of the environment. Packard’s study of Limulus thus provided him with evidence supporting both of the concepts favored by the neo-Lamarckian school: the sequence of development of Limulus, passing through the primitive nauplius and trilobitic stages before adopting the adult form, supported Cope and Hyatt’s principle of acceleration and retardation, while the effect of harsh conditions on Limulus eggs spoke for the modification of organisms by Lamarckian factors. Lamarck, however, was not mentioned in this paper. It is apparent that Cope and Hyatt were more influential in Packard’s conversion to evolution than was Lamarck.

Packard wrote his first paper on Limulus in 1870; his nineteenth and last was published in 1900. Curiously, very little mention is made after 1872 of either of the two principles stated above. The single exception is in a discussion of the derivation of the variety of jointed limbs of Arthropods: “These varieties of

46. Alpheus S. Packard, “On the Development of Limulus polyphemus,” Mem. Boston Sot. Nat. H&t., 2 (1872), 197.

47. Ibid., p. 168.

438 STEPHEN BOCKING

shape can be explained by adaptation to changed conditions resulting from a change from an aquatic to a terrestrial life, or from simply swimming to walking on the bottom or to burrowing in sand and mud.“4s Packards work on Limulus after 1872 focused on its relatedness with other Arthropods, and its likely path of descent from simpler organisms, not on the mechanism of its evolution.

The development of Packard’s ideas on evolutionary mechanisms owed much to this study of the development of the horseshoe crab. Packard also explored other areas of anatomy and morphology, and the conclusions he derived from these studies provided the theoretical basis of his discussions on the effect of the cave environment on animals. In 1875 he published a series of articles on comparative embryology covering the range of animals from the unicellular to the lower vertebrates. (Articles on mammals and man were added the following year.) Packard’s work was based on Agassiz’s principle of recapitulation, reset into evolutionary terms, as Cope and Hyatt had done. According to Packard, the evolutionary development of a taxon would be propelled by the physical factors acting at each point in its history. These factors would operate gradually to change the life history of each individual: “we do not see but that in a long course of generations of the ancestors of the present species of amphibians, the metamorphoses may have become gradually established, finally becoming the normal history of each individual; the changes of the individual epitomizing the successive stages in the collective life history of the entire group of Amphibians.“4y

The life history of an organism with a metamorphosis, each stage of the organism’s life being adapted to a specific environment, was used by Packard in one of his most famous essays in support of neo-Lamarckism: “These different stages, the result of adaptation, are signal examples of the inheritance of characters at corresponding periods of life, and would appear to have been originally the result of the inheritance of characters originated or acquired during the life of the individual.““’

The study of the embryology or life histories of animals, with the demonstration of the recapitulation of their evolutionary history, was an extremely important component of Packard’s work

48. Alpheus S. Packard, “Further Studies on the Brain of Limzthrs polyphemus, with Notes on its Embryology,” Mem. Nat. Acad. Sci., 6 (1893), 3 16.

49. Packard, “Mode of Growth,” p. 644. SO. Alpheus S. Packard, “On the Inheritance of Acquired Characters in

Animals with a Complete Metamorphosis,” Proc. Amer. Acad., 29 (I 894), 350.


in developing and promoting a neo-Lamarckian evolutionary theory. His work with cave fauna provided an opportunity to demonstrate the power of the physical environment as an evolutionary mechanism. The operation of this mechanism could help explain the embryological patterns of recapitulation he observed.

This mechanism could also explain the course of the history of life as determined by paleontologists. Packard believed that paleontology demonstrated that “biological evolution has been primarily dependent on physical and geological changes.“5’ Furthermore, physical, and hence biological, changes have not been random: “The scientist, as such, can scarcely deny that this process of evolution . . . has gone on in an orderly and progressive way. The impression left on the mind is that all these changes, inorganic and organic, have been purposive rather than fortuitous, the result of the action of natural laws, impressed on matter by an intelligence and force outside of, but yet immanent in, all things material.“5’ Packard concluded that progressive physical and biological change was not only initiated but is still being guided by “an infinite intelligence and will.”

Once Packard became an evolutionist, he saw no contradiction between his religious convictions and evolution; he described as “short sighted” anyone who did.5” In fact, evolution provided another illustration of the power of God: “Indeed, to the student of nature, the evolution theory . . . revealing to us the mode in which the Creator of the Universe works in the world of matter, [forms] an immeasurably grander conception of the order of creation and its Ordainer, than was possible for us to form before these laws were discovered and put to practical use.“5J

PACKARD AND CAVE FAUNA

Packard’s first experience with cave animals came in 1871, when he examined specimens obtained from Mammoth Cave. He became keenly interested in them after this, and his first published study of them in 187 1 began a series of papers on the subject that continued for thirty-one years, and included a major monograph, published in 1888. He subsequently examined Mammoth Cave and several of the smaller adjoining caves in April and May 1874,

5 1, Alpheus S. Packard, “A Half-Century of Evolution, with Special Refer- ence to the Effects of Geological Changes on Animal Life.” Amer. Nat., 32 (IX%), 633.

52. Ibid.. p. 673. 53. Packard, Otrr ~‘omtnorr Insects, p. 152. 5-l. Ibid.. p. 153.

440 STEPHEN BOCKING

when he was attached to the Kentucky Geological Survey, under the direction of his former classmate Prof. Nathaniel S. Shaler. With the encouragement of Shaler he also visited the Wyandotte and Bradford Caves in Indiana, and Weyer’s Cave and Cave of the Fountains in Virginia.55 In the summer of 1875, as a member of the United States Geological and Geographical Survey of the Territories, he visited Clinton’s Cave in Utah. Finally, he visited Newmarket Caves in 1879, and Luray Cave in June 1880.“” As is usually the case with studies of American cave fauna, his observations in the most famous cave, Mammoth Cave, were the most extensive.

The opportunity for Packard to examine Mammoth Cave specimens in 1871 came after the Indianapolis meeting of the American Association for the Advancement of Science. Many members of the AAAS had accepted the invitation of the Louis- ville and Nashville Railroad to visit the cave, 180 miles away. Ac- counts of the fauna in the cave were published in the American Naturalist in December 1871 and January 1872, and subsequently as a separate volume; Packard and his colleague at the Peabody Academy, Frederic Ward Putnam, split the work between them, Putnam discussing the fish, and Packard the crustaceans and in- sects5’ Packard’s account was not based on his own observations, but relied on collections made by others - especially Caleb Cooke, also of the Peabody Academy - and on published reports by Cope, Tellkampf, and, for European cave fauna, the Danish zoologist Schiodte.“8

The examination of the cave fauna specimens in 1871 convinced Packard of their usefulness as a demonstration of evolution. Anxious to encourage others to help in gathering evidence for the fact of evolution and for the ability of the environment to modify organisms, he expressed the hope that “our western naturalists will thoroughly explore the sinks and holes in the cave country of the

55. Alpheus S. Packard, “The Invertebrate Cave Fauna of Kentucky and Adjoining States,” Amer. Nut., 9 (1875), 274.

56. Packard, “Cave Fauna of North America,” pp. 3-4, 19. 57. Putnam arrived at conclusions directly opposed to Packard’s He did not

believe that the existence of blind fish in caves was evidence for evolution, and he argued that the neo-Lamarckians base their evidence for transitions, acceleration, or retardation on those characters (eyes and ventral fins) which are of the least importance to the structure of the fish (Frederic W. Putnam. “The Blind Fishes of the Mammoth Cave and their Allies,” Amer. Nut., 6 [I 8721, 6-29). Neither Packard nor Putnam referred to the other’s view in their papers.

58. Alpheus S. Packard, “On the Crustaceans and Insects,” Amer. Nat., 5 (1871) 744-761.


western and middle states. The subject is one of the highest interest in a zoological point of view, and from the light it throws on the doctrine of evolution.“i”

Packard found the most striking evidence for the modification of the cave fauna in Tellkampfs original description of the blind crayfish, Carnbams pellucidus, where he had remarked that “the eyes are rudimentary in the adults, but are larger in the young.““” Packard concluded that the embryo represented the original, unmodified form of the ancestors of today’s blind crayfish:

We might add that this is an evidence that the embryo develops like those of the other species; and that the inheritance of the blind condition is probably due to causes first acting on the adults and transmitted to their young, until the production of offspring that become blind becomes a habit. This is a partial proof at least that the characters separating the genera and species of animals are those inherited from adults, modified by their physical surroundings and adaptations to changing conditions of life, inducing certain alterations in parts which have been transmitted with more or less rapidity, and become finally fixed and habitual.” ’

In citing the embryological development of the blind crayfish as an argument for the modification of the animals by physical factors, Packard used the same reasoning as he would in his later discussion of the metamorphosis of insects. Features appearing at a specific stage in an organism’s life could only have been produced by the conditions of life present at that time. This made it possible to separate those characteristics of animals that had been inherited from those that had been produced by the environment. This information was valuable enough to supply the major justification for work in embryology: “We can now understand, why embryologists are anxiously studying the embryology of animals to see what organs or characteristics are inherited, and what originate de novo, thus building up genealogies, and forming almost a new department of science: comparative embryology in its truest and widest sense.““’

Near the end of his career, in 1894, Packard reviewed the many cases in which blind animals had been found to possess more-

5Y. Ibid., p. 752. 60. Ibid., p. 750. 6 I. Ibid.. pp. 750-75 1. 62. Ibid.. p. 75 1.

442 STEPHEN BOCKING

developed eyes in their youth. He confidently predicted that “future embryological study will farther demonstrate their origin from ancestors with normal eyes.““’

Packard’s eagerness to gather support for evolution outran his supply of clear-cut evidence in favor of such a view. Arguing that the adaptations developed by the cave fauna fulfill the predictions of evolutionary theory, his reasoning became more than a shade circular. First he claimed that “the strongly marked characters which separate the animals from their allies in the sunlight, are just those fitting them for their cave life and those which we would imagine would be the first to be acquired by them on being removed from their normal habitat.“‘j4 This argument implies that there are particular modifications that can be expected to appear when the animal is subjected to the cave environment. However, in establishing an additional point in favor of evolution, Packard states that animals vary in the modifications that are produced by the cave environment: “We thus see that these cave animals are modified in various ways, some being blind, others very hairy, others with long appendages . . . All are not modified in the same way in homologous organs; another argument in proof of their descent from ancestors whose habits varied as their out-of-door allies do at present.““5

For three years following his work in 1871 on the Mammoth Cave specimens, Packard was apparently too occupied with entomological work to devote significant time to cave fauna. The only paper on cave fauna written in this period is a description, published in 1873, of specimens from caves in Indiana received by the Museum of the Peabody Academy of Natural Sciences.“” Several of the species Packard described had been previously described by Cope when he had been invited by the state geologist of Indiana to examine the Wyandotte Cave. Packard found it necessary to correct Cope in three separate instances: he rejected Cope’s designation of a new species of isopod, Caecidotoea microcephala, which was identical to Packard’s designation in 187 1 of Caecidotoea stygia, and he corrected Cope’s description of this animal’s uropoda as “egg-sacs.“” The third point of contention was Cope’s creation of a new species and genus,

63. Alpheus S. Packard, “On the Origin of the Subterranean Fauna of North America.” Amer. Not.. 28 (1894), 738.

64. Packard, “On the Crustaceans,” p. 7.59. 65. Ibid., pp. 760-6 1. 66. Alpheus S. Packard, “On the Cave Fauna of Indiana.” I’enhotljl Acd.

Sci.. Ann. Rep., 5 (1 X73), 93-97. 67. Ibid., p. 96.


Orconectes inermis, to accommodate the single crayfish he found at the Wyandotte Cave and to distinguish it from 0. pellucidus of Mammoth Cave.“” Packard could not find justification for the new species, being unable to “find any but the slightest differences in the proportion of different parts, or in ornamentation; such differences as do exist seem to be simply individual.““” He also rejected Cope’s creation of the new genus Orconectes to accommodate the blind crayfish. Although he shared Cope’s desire to demonstrate that the environment could modify organisms, he could not go along with Cope in his effort to show that the environment could produce not just specific but also generic changes in animals, at the expense of conservative taxonomy. He therefore agreed with H. Hagen in his rejection of the new genus: “The absence of pigment in the eyes, and the loss of sight, I should scarcely regard as of generic value, and am hence inclined to follow Dr. Hagen in retaining pellucidus in the genus Cambarus.” “I In correspondence with Stephen Forbes in 1876 Packard continued to place this species in Cambarus;” five years later, however, when describing an additional blind crayfish from Cope’s collection of the Nickajack Cave, he placed it within the genus Orconectes, naming it 0. hamulatus. Packard and Cope argued that “0. hamulatus presents the same generic characters as 0. pellucidus” and so they were “justified in separating the genus from Cambarus.“”

By the time Packard published his 1888 monograph on the cave fauna, his support for the new genus had faltered. He protested Walter Faxon’s rejection of generic status for Orconectes, but he hesitated to propose it as a full genus, because so many other arthropod genera consist of both eyed and eyeless species. He felt, though, that “due consideration should be given the fact that such loss, total or partial, of the organs of vision is of profound significance, more so than the mere systematic zoologist is apt to recognize.“73 As a compromise, therefore, he urged that Orconectes be considered a subgenus.

Another case in which there was a lack of consensus over

68. Edward D. Cope, “On the Wyandotte Cave and Its Fauna.” Amer. ‘Nat.. 6 (1X72).419.

69. Packard, “Cave Fauna of Indiana,‘. p. 94. 70. Ibid. 71. A. S. Packard to Stephen A. Forbes, Illinois Natural History Survey

Archives, University of Illinois Archives, Urbana, February 1.3, 1876. 72. Edward D. Cope and Alpheus S. Packard, “The Fauna of the Nickajack

Cave.” Amer. Nat., 15 (1 X81), 877--X82. 73. Packard, “Cave Fauna of North America,” p. 42.

444 STEPHEN BOCKING

generic status of cave fauna was that of the isopod Caecidotaea stygia. The description of this species was hindered by the lack of adequate specimens. Packard’s original description in 1871 was based on a single damaged specimen, which led him erroneously to ally the new genus with the genus Zdotea. This introduced a new difficulty: the nearest allies of this species were, with two exceptions, exclusively marine. Packard could not see how the species could have been established as a cave dweller.”

The mystery was solved when Packard later received “numerous specimens in a better state of preservation,“‘” and so two years later, in 1873, he published a correction, placing Caecidotaea within the family Asellidae rather than the Idotaei- dae.‘” He complained that he could not change the generic name from Caecidotaea to the more apt Caecasellus, but was forced to “defer to the present rule of nomencalture, that one author can not change a name based even on an unfortunate error.“” Some authorities denied the validity of the genus. One of the most prominent, Stephen Forbes, decided, after comparing specimens with known Asellus, that there were no “structural peculiarities which could possibly serve as the characters of a distinct genus, and I have therefore united it to Asellus.“‘” Packard continued nonetheless to use the genus, adding a new species, Caecidotaea nickajackensis, in 1881.7y He argued: “We think we have shown that on taxonomic grounds the genus Caecidotaea is as well founded as many other genera which are accepted by carcinologists. It presents, at any rate, certain constant differences from the blind species of European wells and caves, as well as the dark abysses of Lake Geneva, and though exposed to the same general surroundings, has developed in different directions. It affords an interesting example of the origin of generic characters by changes in an environment the nature of which we can easily estimate.“S”

In most cases, Packard resisted the refusal of systematists to create separate genera for blind species. He felt that they were often not able to understand the importance that some characteristics have in the natural environment. As a naturalist with an

74. Packard, “On the Crustaceans,” p. 752. 75. Packard, “Cave Fauna of Indiana,” p. 96. 76. Ibid., p. 96. 77. Packard, “Cave Fauna of North America,” p. 30. 78. Stephen A. Forbes, “List of Illinois Crustacea, with Descriptions of New

Species,” Ill. MIS. Nat. Hist. Bull., 1 (1876) 1 1. 79. Cope and Packard, “Nickajack Cave,” p. 879. 80. Packard, “Cave Fauna of North America,” p. 34.


abundance of field experience, he considered it a “great conve- nience” to use special names for specialized groups such as the blind “genera,” and at any rate, “they are founded on characters which are certainly of more fundamental importance than hundreds and even perhaps thousands of genera which pass current at the present day, and are founded on characters of trivial importance.” ”

Packard’s treatment of Caecidotaea stygia’shows an increasing theoretical sophistication as his familiarity with cave fauna increased. In several important areas, however, his conclusions did not change over the course of his career. Discussions of some issues in his latest papers were simple restatements of conclusions arrived at as much as a quarter-century before. Most obviously, his conviction that cave fauna demonstrated the primacy of Lamarckian factors in evolution never wavered. However, his views on the operation of Lamarckian factors changed greatly over the years.

One theory that did stay relatively constant over Packard’s career concerned the age of the caves and hence of the fauna. This was a crucial question, because the geological age of the caves established an upper limit on the time available for the distinctive cave fauna to have been produced. Any evolutionary mechanism would have had to operate within the limited time available to it. A relatively recent origin of cave fauna would favor a Lamarckian mechanism, because this mechanism did not require the “numberless generations” considered necessary for natural selection to act.

In 187 1 Packard concluded, from evidence supplied by Cope, that the cave fauna were indeed of very recent origin. Cope claimed that only the torrents of running water that were supposed to have occurred at the end of the last ice age could have produced the caves. Furthermore, the caves did not contain the remains of any animals predating the most recent (Quaternary) geological period. Packard concluded therefore that “the species of the subterrean fauna the world over are recent creations, probably not older than the extinct mammals associated with man.““’ This apparently rapid development of the cave fauna eliminated natural selection as a possible mechanism. It was, though, strong support for the alternative to natural selection supplied by Packard’s colleagues: “But the comparatively sudden creation of these animals affords, it seems to us, a very strong argument for the theory of Cope and Hyatt of creation by acceleration and retarda-

81. Ibid., 121. X3. Packard. “On the Crustaceans.” p. 75X

446 STEPHEN BOCKING

tion, which has been fully set forth in this journal.“S” Seventeen years later Packard reaffirmed the recent origin of cave fauna, calculating it “as not much over from 5000 to 10,000 years before the dawn of history, which itself extends back some 5000 to 6000 years.” s4 Again, he stressed that only neo-Lamarckism offered a way out of the apparent dilemma caused by the rapid evolution of the cave fauna: “The biologist, in seeking an explanation of this peculiar troglodyte assemblage, need not demand the “numberless generations” insisted on by Mr. Darwin in his Origin of Species. The time since the present climatic relations and the present fauna came into existence may, it seems to use, be estimated by a few thousands rather than by hundreds of thousands of years.“Ss

Packard always considered the rapidity with which neo- Lamarckian evolution could work as important evidence in its favor. However, his conception of how fast it could really act changed over the years. Although he was often inconsistent, his overall trend over the years was to expect evolution to act more quickly. His first hypothesis in 1871 was that “geologically speak- ing the species were suddenly formed, though the changes may not have been wrought until after several thousand generations.“Sh By 188 8 he had drastically shortened the time necessary: “While the eyeless and abyssal forms (both freshwater and deep-sea) may have existed for many generations, for periods of hundreds and possibly thousands of years, yet the following facts tend to show that the bleaching of the body and atrophy of the eyes, as well as the adaptations to a life in darkness, may have been induced after but a few generations, perhaps but one or two only, resulting in the comparatively rapid evolution of cave species.“X7 It is clear that Packard was prepared to postulate such rapid evolution because of the increased confidence he had in the ability of the environment to modify organisms. He never explicitly abandoned Cope and Hyatt’s theory of evolution by acceleration and retardation; however, except for one isolated reference to it in his 1888 monograph, he did not mention it in connection with cave fauna again.“s There were aspects of both Cope’s and Hyatt’s versions of

83. Ibid., p. 759. 84. Packard, “Cave Fauna of North America,” p. 23. 85. Ibid., pp. 23-24. 86. Packard, “On the Crustaceans,” p. 759. 87. Packard, “Cave Fauna of North America,” p. 139. 88. Packard described two female orthoptera. one having a normal ovipositor,

the other having one only one-third as long and hence less sexually mature. This showed that “the principle of acceleration and retardation may work in caves as well as out of doors; in this case sexual development was much retarded” (Packard, “Cave Fauna of North America,” p. 69).


their theory that made them incompatible with Packard’s views. Their theories postulated nonadaptive trends in evolution, whereas Packard believed that all evolutionary change led to greater adaptation of an organism to its environment. In his view, the complete control exerted by the environment on evolution precluded trends toward racial senility like those described by Hyatt. Packard’s lack of reference to the theory of acceleration and retardation, and the fact that he had cited only the weak evidence of the apparently rapid evolution of the cave animals as evidence in favor of the theory, indicate that his allegiance to it was not strong. Even in 1871, more weight was given to the immediate effect of the environment: generic and specific characters were the result of physical factors acting on the adult forms of the animals. These modifications eventually were transmitted to the young.sy

On several occasions, Packard offered examples that showed outdoor animals in the process of adapting to the cave environment. In these cases, evolution could be seen actually working:

I found in the Carter Caves several specimens of S[piuostre- phon] cavernarum which were reddish-brown, and had apparently larger eyes than the normal white examples characteristic of the Carter and Wyandotte Caves. I regard it as extremely probable that this reddish race has not been established long enough in the cavern to lose its original brown color. We here see, in fact, a cave species in process of formation, and I regard this as one of several facts . . . tending to prove that nearly all the cave animals are modified forms living at the present day out of doors.‘”

By the time of his 1888 monograph on cave fauna: Packard’s work is marked by a seemingly inexhaustible confidence in the power of neo-Lamarckism. Neo-Lamarckism in the case of cave fauna was more than just the effect of the environment on organisms; it was, rather, “a complex assemblage of physical causes, all working together.““’ The causes included a change in environment from light to darkness, diminution of food, “compensation for the loss of certain organs by the hypertrophy of others,” disuse of organs, adaptation, isolation from intercrossing with “out-of-door forms,” and heredity, establishing the newly acquired

X9. Packard. “On the Crustaceans,” pp. 750-5 1. 90. Packard. “Cave Fauna of Kentucky,” p. 277. Y 1, Packard, “Cave Fauna of North America,” p. 13X.

448 STEPHEN BOCKING

forms as permanent, as long as the environment remained constant.“’

The hypertrophy of other organs as compensation for the loss of vision was often described. This consisted of the lengthening of the body and its appendages, possibly accompanied by improve- ments in the sense of touch, the development of specialized tactile organs, and an increased sense of smell. It was an open question whether hearing was improved in blind animals. Packard made no attempt to account for the development of other senses by citing the Lamarckian principle of use stimulating the growth of an organ. Nor could natural selection be responsible - how could it, when, as was generally agreed, competition was much less significant in caves? Darwin, for example, expected that relics of “ancient life” would be preserved in caves, “owing to the less severe competition to which the inhabitants of these dark abodes will probably have been exposed.“‘” The only possible mechanism was the direct action of the absence of light: “On the other hand, the limbs tend to grow larger, to perhaps exert a tactile sense; and this trait, being favorable to the species, is gradually further developed, until it becomes fixed in the organism by heredity. The result is that all the individuals become long-limbed and blind. There is apparently no struggle for existence, but the direct influence of darkness, united with heredity, are plainly the immediate agencies in the transformation.“‘”

Packard did not attempt to explain how the absence of light could be responsible for these modifications by which “nature has compensated these apparently hapless forms for their loss of eye-sight.““’ Instead, he attempted to show by numerous examples that the increased development of other senses more than makes up for the loss of vision. Apparently nature, acting teleologically, will provide these adaptations whenever the physical environment demands them. The loss of eyesight therefore is consistent with the process of progressive evolution, because vision will be replaced by other, more useful senses.

The concept of heredity held by Packard resembled the memory analogy applied by many Lamarckians: there is a cumulative effect in which environmentally induced modifications are reinforced as generation after generation live and reproduce in a constant environment. For cave fauna, Packard wrote, heredity

92. Ibid. 93. Darwin. Origin ofSpecies. p. 13X. 94. Packard, “Cave Fauna of North America.” p. 13X 95. Ibid., p. 124.


“operated to secure for the future the permanence of the newly originated forms as long as the physical conditions remain the same.” ” As long as the environment remained unchanged, heredity would act with “increasing force and precision as time goes on and the characteristics induced by a life in total darkness become more and more fixed.““’ The results of this process of heredity would continually become more apparent. Thus, heredity had acted longer in those species that had no trace of eye or optic nerve than in those that still had rudimentary eyes, Packard argued against Karl Semper’s proposal that the blindness of the mole “is the result not of inheritance, but of the directly injurious effects of darkness on the optic nerve in each individual.“‘”

Packard’s confidence in neo-Lamarckism led him to dismiss objections that some cave animals had well-developed eyes, or that a genus of cave beetle had blind females, but males with well- developed eyes. He stated flatly that “it may be laid down as an axiomatic truth that where eyes are defective or atrophied, it is owing to disuse induced by physical surroundings of such a nature as to enable the animals in question to dispense with organs of sight.“Y’Y All the exceptions could then be explained away: the cave forms with eyes either were not isolated from out-of-door forms, were “twilight forms rather than denizens of absolute darkness,” lo0 or were lacking an optic nerve, and were therefore blind.‘“’

The life in the ocean depths offers another example of how Packard’s faith in neo-Lamarckism exceeded the available evidence. Abyssal life was of interest because there was “an interesting and suggestive parallel to the conditions of cave life. It is most probable that the causes of atrophy or blindness under one set of conditions are the same or nearly the same in the other.“lo2 Packard quoted at length S. I. Smith’s account of decapod crustacea dredged in the western North Atlantic. Smith had concluded that “although some abyssal species do have well- developed black eyes, there can be no question that there is a tendency towards very radical modification or obliteration of the

96. Ibid.. p. 13X. 97. Ibid.,p. 131. 98. Karl Semper. Arziffra/ Life as Afected by the Natural Conditions of

Exi.stence (New York, 188 1). p. 80; as quoted in Packard, “Cave Fauna of North America.” p. 142.

W. Packard, “Cave Fauna of North America,” p. 132. 100. Ibid..p. 131. 101. Ihid.,p. 132. 102. Ibid.. p. 133.

450 STEPHEN BOCKING

normal visual organs in species inhabiting deep water.““‘” Yet some deep-sea species possessed large and apparently normal eyes, which made it probable, “in spite of the objections of the physicists, that some kind of luminous vibrations do penetrate to depths exceeding 2000 fathoms.” lo4

This idea had already been suggested by the marine biologist at Yale, Addison E. Verrill, one of Packard’s fellow students under Agassiz. It was quickly ridiculed by an influential authority, Prof. H. N. Moseley, who described it as “entirely at variance with the results of all experiments on the penetration of sea-water by sunlight as yet made by physicists.” lo5

The need to develop such absurd supporting evidence as the possibility of light reaching 12,000 feet down into the depths certainly bears witness to the weakness of the position. Packard was nonetheless impressed by the “striking parallelism between the deep-sea blind Crustacea and those inhabiting caves.” He hoped that additional research would show that “the forms with well-developed eyes are twilight forms, which live between the dimly lighted superficial and the deepest layers of the water, and not wholly restricted to the totally dark abysses. Moreover, it may be found that the forms without eyes burrow in the ooze or live under loose objects at the bottom, and thus live in a darkness still more profound than those which simply hover over the bottom.” lo6

PACKARD AND THE NEO-DARWINIANS

Packard never failed to stress that the cave fauna testify more in favor of Lamarckian factors than of natural selection. The increasing stridency of his advocacy of neo-Lamarckism in the latter part of his career reflects the polarization that had developed by 1890 between neo-Lamarckians and those favoring natural selection. As Vernon Kellogg emphasizes, many were not strongly in one camp or the other, and “it is only neo-Darwinism (of Weismann, Wallace, and others) and neo-Lamarckism (of Spencer, Packard, and others) that are so radically opposed, so mutually exclu- sive.” In7 Packard’s studies of cave fauna, together with his studies

103. Ibid., p. 134; quoting from S. 1. Smith, Ann. Mug. Nat. His., 5th ser., (1886), 194-197.

104. Packard, “Cave Fauna of North America,” p. 134. 105. H. N. Moseley, “Opening Address [on Deep Sea Research],” Nuture, 30

(1884), 425-429. 106. Packard, “Cave Fauna of North America,” p. 135. 107. Vernon L. Kellogg, Darwinism To-day (New York: Henry Holt and

Company, 1907), p. 264.


in embryology, exhibit the effect of this polarization. They also helped to establish him as a leading promoter of neo-Lamarckian theories. By 1890, Packard’s style had changed from very infrequent reference to opposing views, to a position stressing that natural selection was inadequate, and that only the inheritance of acquired characteristics could explain the origin of the phenomenon being studied. For Packard, it was “axiomatic that the primary factors of evolution were neo-Lamarckian”; ‘(M the point was to convince the naturalist community that any phenomena - ranging from the adaptations of cave fauna, to the life histories of invertebrates, to even those phenomena that were most often described as support for natural selection (such as mimicry) - could be explained by neo-Lamarckian principles.

One historian has stated that Packard “made special efforts to reconcile Lamarckism to Darwinism.” I”” In fact, in those areas of zoology in which Packard specialized, and especially in the case of cave fauna, natural selection was relegated to a position of insignif- icance, playing a “very subordinate and final part in the set of causes inducing the origin of these forms.““” Natural selection could never operate in more than the final stages of evolution, acting upon the variations produced by the more “fundamental” factor of neo-Lamarckism. In Packard’s time, the predominant opinion among opponents of the neo-Darwinians was that natural selection could initiate nothing, being “dependent wholly for any effectiveness on some primary factor or factors controlling the origin and direction of variation.” ’ ’ ’ Natural selection could only eliminate unfit varieties. Packard’s adherence to this view does not imply a special effort of reconciliation of the two mechanisms.

For Packard, the truth of the neo-Lamarckian school was self-evident. Those who were unable to recognize the preeminence of the inheritance of acquired characteristics could not do so, he asserted, because “the dogma or creed of natural selection has . . . tied their hands, obscured their vision, and prevented their seeking by observation and experiment to discover, so far as human intelligence can do so, the tangible, genuine, efficient factors of organic evolution.” ’ ” Darwin himself had once fallen in this trap, until, as Packard recounts, he reacted against the overimportance given natural selection, and accorded Lamarckian factors more

108. Packard, “Cave Fauna of North America,” p. 132. 109. Ralph W. Dexter, “The Impact of Evolutionary Theories on the Salem

Group of Agassiz Zoologists (Morse, Hyatt, Packard, Putnam),” Essex Inst. Hist. Collect., 115 (1979), 167.

110. Packard, “Cave Fauna of North America,” p. 143. 1 11. Kellogg, Durwinism, p. 27. 1 12. Packard, “Cave Fauna of North America,” p. 143.

452 STEPHEN BOCKING

importance. Packards real target in discussing the evolution of cave fauna was not Darwin but “some naturalists of the neo- Darwinian school [who] reject the operation of the Lamarckian factors and illogically attribute the creation of this wonderful assemblage of blind forms to natural selection, and others to panmixia - i.e. the cessation of natural selection.” ’ ’ 3

August Weismann and Edward Ray Lankester received the greatest amount of Packard’s criticism. Packard in the past had had the greatest respect for Weismann, even translating several chapters of Weismann’s Development of Diptera and publishing them in the American iVaturalist.“4 Packard was all the more disappointed, therefore, that Weismann had deviated from Lamarckian reasonableness into Darwinian obstinancy: ‘Weis- mann, who has rendered such eminent service to biology, in establishing the principle of heredity on a physical basis, as is well- known, pushes aside all these factors and explains the blindness of cave animals by a negative cause, ‘panmixia,’ i.e. the absence of natural selection . . . he thus substitutes for the positive, tangible factors of change of environment, disuse and isolation, the negative and hypothetical one which he calls ‘panmixia.‘“‘15

Lankester, Packard’s other major target among the neo- Darwinians, had written that the blindness of the cave animals was due to a peculiar form of natural selection. He began with the assumption that some animals are, by chance, born with defective eyes. Occasionally a few animals, some of which have normal eyes and others have defective eyes, will fall or be swept into caves. In each generation, those that have good eyes will be able to see the light and can escape, and eventually only those that are blind will remain in the cave.‘Ih Packard criticized Lankester for postulating the existence of “fortuitous” variations, arguing that there is some question as to whether “they can arise independently of and are not controlled by the ever active forces of nature.“‘17 He also depicted Lankester and Weismarm as two scientists who allow their speculations to outrun their familiarity with the research: “It is apparent that both of the last named writers, who have not themselves had a practical experience in collecting and studying

113. Alpheus S. Packard, “Cave Animals,” in New International Encyclopedia (New York: Dodd, Mead, 1902-04), p. 260.

114. Alpheus S. Packard, “The Metamorphosis of Flies, Translated from A. Weismarm,” Amer. Nat., 8 (1874) 603--612,661-667,713-721.

115. Packard, “On the Origin,” p. 741. 116. Edward R. Lankester, “Blind Animals in Caves,” Nature, J7 (lt193),

389. 117. Packard, “On the Origin,” p. 743.


cave animals and their surroundings, nor have carefully read the recent literature on the subject, are overmastered by speculative views, and prefer to make an extremely vague, unscientific and a priori speculation, rather than adopt an opinion based on the inductive method.” ’ Is

A look at the way in which Packard discussed the theoretical cave work of another naturalist indicates that his real aim in criticizing Lankester’s and Weismann’s theories was not so much to defend his own theories, as to discredit the Darwinists. In the 1894 review paper that I have quoted, Packard discussed exten- sively the theories of Professor Harry Garman of Illinois. Garman’s paper had disagreed with several points that were central to Packard’s interpretation of cave fauna. These included the tenets that the absence of light was responsible for the loss of eyes, that the recent origin of the caves implied the recent origin of the cave fauna, and that isolation was an important factor in the evolution of cave animals.‘” Garman’s major conclusion was that “it seems only required that a species have no use for eyes, irrespective of the presence of light, and the eyes become reduced.” ’ *” The cave fauna were probably already adapted to cave conditions before moving to their present habitat. And yet Packard did not criticize Garman’s views, despite their incompat- ibility with his own. The difference between this treatment and his treatment of Weismann and Lankester is striking. Garman was not a prominent member of the Darwinian school, as Lankester and Weismann were. It is likely that this saved him from Packard’s attack.

CAVE EVOLUTION AFTER PACKARD

Other biologists continued the study of cave fauna after Packard published his last article in 1902. Carl Eigenmann, ichthyologist and Professor of Zoology at Indiana University, became interested in the study of the cave as a uniform “unit of environment,” a phenomenon that could help in the investigation of the causes of variation. Like Packard, Eigenmann accounted for the blindness of cave animals by the inheritance of the effects of the environment, but his description of cave evolution as “degenerative” indicates that he did not share Packard’s view of cave

118. Ibid., p. 744. 119. Harry Garman, “The Origin of the Cave Fauna of Kentucky, with a

Description of a New Blind Beetle,” Science, 20 (1892), 240-241. 120. Ibid., p. 240.

454 STEPHEN BOCKING

fauna as an illustration of progressive evolution. He followed Garman in arguing that many types of cave fauna had already become adapted to the cave environment before entering caves, and he stressed that the “origin of the cave fauna and of the blind fauna are two distinct questions.“r’l This conclusion became inescapable when he discovered that blind fish could also be found outside of caves. For example, he studied one population occurr- ing among rocks on the California seacoast. The age of the caves could not then be tied to the time available to the cave fauna for modification, as Packard had assumed. No longer could the necessity of rapid evolution in recently formed caves be used as evidence for neo-Lamarckian evolution.

Eigenmamr’s student, Arthur M. Banta, was more skeptical than his teacher of the Lamarckian explanation. Until it is demonstrated experimentally, Banta argued in 1907, “the explanation of the origin of blind and colorless cave forms through the heredity of the effects of disuse and of the influence of the lack of light can not be very satisfactory.“rz2 Banta was more receptive to Henry Fairfield Osborn’s notion of the cumulative effect of determinate variations. Following Banta’s application of this theory to cave fauna, animals having a maladaptive evolutionary trend toward blindness would be forced into caves, for only there could they survive. In 1921 Banta suggested an alternate mechanism based on the mutation theory popular among geneticists. Examining large numbers of Cladocera, he found one lacking eyes, which he supposed had undergone a mutation analogous to the “bar-eyed” and eyeless mutations of Drosophila. Banta suggested that if this mutation is inherited then it could explain the origin of the cave fauna, as only in that environment would this mutant be able to survive.12”

Although there was skepticism, and some, like Banta, tried to fit cave evolution into alternative theories like those of Osborn and T. H. Morgan, cave fauna continued until recently to be used as an example of the inheritance of acquired characters by prominent European neo-Lamarckians, including Paul Kammerer,‘24 E. W.

121. Carl H. Eigenmann, Cuve Vertebrates: A Study in Degenerative Evolu- tion (Washington, D.C.: Carnegie Institution, 1909), p. 12.

122. Arthur M. Banta, The Fauna of Mayfields’s Cave (Washington, D.C.: Carnegie Institution, 1907) p. 104.

123. Arthur M. Banta, “An Eyeless Daphnid, with Remarks on the Possible Origin of Eyeless Cave Animals,” Science, 53 (1921), 462-463.

124. Philip G. Fothergill. Historical Aspects of Organic Evolution (London: Hollis and Carter, 1952) p. 254.

Alpheus Spring Packard and Cave Fauna 4.55

MacBride,‘2s and R. Jeanel.“6 The leading French cave biologist of the twentieth century, Albert Vandel, used cave fauna to demonstrate his theory of “organicism.” According to this theory, all phyletic lines pass through a series of stages: the creation of a new organic type, expansion and diversification, and, eventually, specialization and senescence, resulting in the extinction of the group. The evolution of cave fauna is an example of the regressive evolution that will occur only in the final stages of the evolution of animal lines. This evolution is independent of changes in the environment.“’

The development of the modern synthesis completed the process of eliminating the direct effect of the environment as a viable mechanism for the evolution of cave fauna. There is no consensus, however, on a Darwinian replacement. Natural selection, involving increased metabolic efficiency or the indirect effects of pleiotropy, is favored by some, while others have suggested the accumulation of neutral mutations.‘2s In spite of its anti- Lamarckian stance, the modern emphasis on the importance of the isolation of cave fauna, and the correlation between time spent in the cave environment and morphological change, can be seen as a partial revival of Packard’s views.

CONCLUSION

Packard attempted to incorporate cave fauna into a general theory of evolution that would be consistent with the principle of recapitulation, and would have as the primary mechanism the inheritance of the effects of the environment. Beyond this, he also attempted to demonstrate that the evolution of cave fauna was consistent with progressive evolution. The use he made of comparative anatomy and embryology places him within the tradition of classical morphology that was dominant through much of the last half of the nineteenth century, but of waning importance by the time of Packard’s death in 1905. The importance Packard gave to cave fauna as evidence for Lamarckian evolution stimulated interest in the phenomenon; this interest, and references to cave fauna in the scientific literature, declined after his death. Since

125. E. W. MacBride, “The Blindness of Cave-Animals,” Nnture, 116 (1925), 818.

126. Albert Vandel, Biospeleology: The Biology of Cavernicolous Animnls, trans. B. E. Freeman (Oxford: Pergamon Press, 1965), p. 46 1.

127. Ibid.. pp. 462-463. 12X. David C. Culver, Cave Lift (Cambridge, Mass.: Harvard University

Press, 1 Y82), pp. 56-76.

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then, the importance of cave fauna in evolutionary theory has declined from their status as the star evidence in Packard’s theory to their present status as a difficult anomaly within the modern synthetic theory.

Acknowledgment

I would like to thank Professor Mary P. Winsor of the University of Toronto for many valuable comments on the manuscript.

Alpheus Spring Packard and cave fauna in the evolution debate

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