Chapter Eight—
Strategies for Retrenchment

The revolutionary stirrings in biology at the beginning of the twentieth century created new challenges for Darwinism—for its method, theory, and general outlook. Two groups of scholars played major roles in helping Darwin's scientific legacy survive the crisis and find a functional place in the complex world of the new biology.

The first group grew within the community of Darwinian scholars. Its members were willing and determined to press for a retreat from the more orthodox—and less defensible—positions of Darwinian thought, which, they felt, limited the scope of evolutionary exploration, followed misdirected paths of inquiry, and perpetuated critical lacunae in the systems of theoretical principles. Determined to soften the paralyzing rigidity of orthodox constraints, they did not abandon their basic loyalty to Darwin. They were "unorthodox Darwinists."

The second group consisted of biologists who responded favorably to drastic changes in theoretical and experimental approaches to heredity and to the rise and phenomenal growth of genetics, a science built on Hugo de Vries's mutation theory and Gregor Mendel's mathematical explanation of the mechanism of heredity. Immersed in biological developments outside the classical framework of the Darwinian tradition, these scholars pressed for a redefinition of the nature and evolutionary role of variation and heredity.

These two groups, each in its own way, represented the most fertile developments in Russian biology during the first two decades of the twentieth century. They played primary roles in the ongoing search for a

new and more comprehensive theory of evolution. Both merit more detailed scrutiny. This chapter concentrates on the major representatives of each group, particularly on their suggestions for synchronizing the twentieth-century developments in biological thought and the Darwinian tradition, and for formulating a broader approach to organic evolution.

Unorthodox Darwinism

Unorthodox Darwinists, a clearly identified and rapidly growing group, agreed that, despite their general scientific validity, Darwin's principles required extensive amplification, refinement, and modification in the light of new advances in biology. In "useful" contributions of modern experimental biology they saw much more than the products of research Darwin had anticipated or recommended but did not pursue. In no way, however, were they ready to abandon the idea of natural selection as a decisive factor in the evolutionary process. They shared two distinctive characteristics: they did not work actively in experimental research related to variation and heredity, and they labored primarily on protecting and consolidating the preeminence of Darwin's theory. They helped stem the tide of anti-Darwinism propelled by the more extreme, and rashly generalized, claims of experimental genetics and various branches of neo-Lamarckism.

The representatives of unorthodox Darwinism, like the representatives of strict orthodoxy, regarded Darwin's theory as the quintessential explanation of organic evolution. Unlike the defenders of strict orthodoxy, however, they placed strong emphasis on the urgent need for bringing Darwin's views into a closer working relationship with major developments in modern biological theory. They recognized that modern experimental biology had made significant discoveries in the domains of life that Darwin had left unattended, and that it had produced theoretical insights contradicting some of the leading principles built into Darwin's theory. Darwinism, in the view of these scientists, faced two vital tasks: to absorb the new knowledge that filled in the lacunae in evolutionary thought; and to modify some of its own views in order to facilitate their accommodation to advances in experimental biology contradicting Darwin's theory.

Among the supporters of unorthodox views in the community of Darwinian scholars, four were particularly active: N. A. Kholodkovskii, I. I. Mechnikov, V. M. Shimkevich, and V. I. Taliev. All were united by a

firm loyalty to the basic principles of Darwin's theory, by a conviction that the survival of Darwinism depended on a cautious search for cooperation with new stirrings in evolutionary biology, and by a strong distaste for neovitalism and psychological orientations steeped in metaphysical speculation. Although united in their general views on the current strategy of Darwinian research, these biologists acted strictly as individuals, guided by their specific theoretical ideas and general philosophical attitudes. Some individuals gave the cooperation of Darwinism and selected developments in the experimental studies of heredity a particularly high priority; others favored closer working contact between Darwinism and various branches of neo-Lamarckism.

Nikolai Aleksandrovich Kholodkovskii, professor of biology, first at the Forest Institute in St. Petersburg, and then at the Academy of Military Medicine in the same city, was known for his literary gifts. A translation of Goethe's Faust made him a national celebrity and earned him the coveted Pushkin Prize. He also translated Erasmus Darwin's Temple of Nature into Russian and wrote his own poetry. A noted specialist in entomology and parasitology, he wrote numerous technical and popular articles, some of them reissued in a volume entitled Biological Essays . His popular articles covered such topics as "parthenogenesis," "animal instincts," "human reason," "cell and nucleus," "protective coloration among animals," and "the social life of ants." He dealt extensively with the development of post-Darwinian evolutionary thought.^[1]

Kholodkovskii did not present a systematic discussion of the contributions of de Vries and Mendel to the experimental study of heredity. The meteoric growth of genetics at the very beginning of the twentieth century did not attract his attention. His heavy concern with the rapidly mounting involvement in the theoretical and experimental aspects of variation and heredity did not go beyond the age of Weismann. In fact, he was the first Russian zoologist to undertake a methodical and critical scrutiny of the scientific work of Kölliker, Nägeli, Weismann, Eimer, and other leading evolutionary biologists of the early post-Darwinian era. Written in a popular style, without excessive technical involvement, his essays appealed particularly to general readers interested in the more exciting developments in modern science.

Kholodkovskii thought that Darwin's theory was more comprehensive and more deeply grounded in empirical substance than that of any other naturalist. But he was also convinced that since Darwin left some basic questions unanswered, there was an imperative need for blending his theory with selected contributions by more recent biologists. Darwin,

for example, did not look into the origins of variation: he worked exclusively with variation as ready-made raw material which natural selection either rejects or integrates into the course of evolution. More recent studies, however, showed the close relationship of the mechanisms of heredity to the dynamics of variation. While Darwin asked the general questions related to the origin of species, experimental biologists showed a particular interest in the specific questions related to the origin of variation. Kholodkovskii even welcomed the rebirth of Lamarckism because of its possible complementary relation to Darwinism.^[2]

Kholodkovskii combined a firm adherence to Darwin's views with a careful search for an objective and minute appraisal of the theoretical vistas opened by post-Darwinian scholars. He noted in 1895 that the time had come to admit that the idea of evolution had entered a "new phase of development."^[3] The current—and rapidly growing—interest in the physiological aspect of evolution, the experimental study of the evolutionary role of the environment, the limitless potential of the physicochemical analysis of ontogeny, and the promise of experimental morphology attracted much of his attention.^[4] He wrote in 1898, on the eve of great discoveries—and rediscoveries—that laid the foundations for genetics as a distinct discipline:

Experiment, previously considered a tool used mainly by physiologists, is beginning to find a place in anatomy and embryology. In his study of animal cells, a modern researcher not only is interested in morphological characteristics. . . . but tries to reduce all vital activity and every morphological structure to a physicochemical base (Otto Butschli); he studies the influence of various chemical agents on the nucleus and on the protoplasm; he endeavors to isolate physiological activities (Demoor); and, finally, he devotes particular attention to the process of cell division, depending on the special activity of the centriole, and to the chromatin base of the nucleus.^[5]

Caught in a whirlpool of scientific crosscurrents, Kholodkovskii sensed and recorded the multiple lines of development in the new biology. In 1891 he thought that phylogenetic morphology, tracing its roots to the first generation of Darwinian scholars, would continue to reign supreme for a long time. Seven years later he was ready to admit that the phylogenetic approaches, based on the intricate techniques of observation, had surrendered their preeminent role in evolutionary biology to experimental studies.^[6] In all this, he operated on the assumption that in order to preserve its reigning authority in biology, Darwinism needed methodological retooling and broader theory. In comparison with new developments in biology, Darwinism had a definite edge because it cov-

ered a much broader universe and was simpler in conceptual design and more directly related to the concrete facts of nature.

Kholodkovskii, who knew more about the developments in biology during the 1890s than any other Russian professor of the life sciences, had a keen understanding and appreciation of the threads of thought that led to the emergence of new biological sciences—such as cytology and genetics—and to new research strategies. Greeting the growing specialization in biology, he welcomed at the same time the growing cooperation between various branches of biology, both old and new.^[7] Such an integration, he thought, would achieve two positive results: it would recognize the growing advantage of experimental techniques in modern biology, and it would give new strength and broader meaning to Darwin's theory.

Skeptical about its current achievements, Kholodkovskii was cautiously optimistic about the future of the experimental branches of biology. He showed a particular interest in three orientations that were in the ascendant during the 1890s: Weismann's neo-Darwinism, Wilhelm Roux's "developmental mechanics" (Entwicklungsmechanik ), and various experimental schools rooted in the Lamarckian tradition. In all cases, he was interested primarily in relating individual orientations to the strengths and weaknesses of Darwinism.

Kholodkovskii dealt in some detail with Weismann's theory of heredity as the backbone of the general theory of evolution. This theory appealed to him because it included natural selection as a bridge connecting the notion of germ plasm, the immutable and "potentially immortal" hereditary matter totally independent of external influences, with the idea of organic transformation. This did not stop him, however, from criticizing Weismann's exaggerated emphasis on natural selection. It is not advisable, he wrote in 1897, to view natural selection as "the only or almost the only factor responsible for such a complex phenomenon as organic development."^[8] The rejection of panselectionism was a common trait of Russian representatives of unorthodox Darwinism.

In Kholodkovskii's view, Weismann deserved much credit for two contributions to modern biology. First, he laid the foundations for the modern scientific concern with heredity as a basic mechanism of organic evolution. His "germ plasm," a synthesis of Gallon's "stirps" and Nageli's "idioplasm," served as a basis for the modern recognition of the "material foundations of heredity."^[9] Second, he showed conclusively that the theory of the inheritance of acquired characteristics had no empirical support. Kholodkovskii had two objections to Weismann's theory: it is

laden with impenetrable conceptual structures—and improvisations upon structures—difficult to translate into manageable designs for empirical research, and it cannot account for parthenogenesis.

Kholodkovskii also showed a keen interest in the ambitious effort of the German professor Wilhelm Roux of Halle University to reduce experimental biological data to the universal laws of mechanics, an undertaking that Nägeli initiated in 1884 on a purely theoretical level. He thought that, at least in one respect, Roux's effort was unrealistic and rather pretentious: at the end of the nineteenth century, he contended, science was not yet ready to establish firm links between experimental data and the laws of mechanics.^[10] Roux received credit, however, for advancing a corpuscular theory of heredity based on principles very similar to Weismann's. He "erred" in proposing a shift of emphasis from morphology (Darwin's base of operation) to physiology as the main science of organic evolution, and in exaggerating the advantages of "experiment" over "observation" as the main source of biological knowledge. Far from disparaging the role of experiment in biology, Kholodkovskii merely wanted to note that experiment had not yet become an efficient research tool in the study of organic evolution. Nor did physiology reach a level of perfection that would allow it to occupy a commanding position in unraveling the secrets of the evolutionary process. Darwinism continued to be a dominant approach in the study of evolution for the simple reason that no other orientation was strong enough to take its place.

Lamarckian research in heredity was the third major branch of experimental biology that attracted Kholodkovskii's critical attention. Here, too, his analysis explored the possibility of closer ties between Lamarckian and Darwinian theoretical views and research methods. In his critical review of observations by Max Standfuss in Germany and Shmankevich in Russia, he concluded that, at the current level of the development of biology, it was impossible either to prove or to disprove the direct environmental influence on the emergence of heritable characters.^[11] The fruitful cooperation of Darwinian and Lamarckian approaches was feasible, but it clearly belonged to the undetermined future. Both orientations deserved credit for recognizing the stimulating environment as an important factor of evolution. Kholodkovskii favored the development of Lamarckism and Darwinism as complementary theories. While Darwinism, he thought, held the keys to an understanding of the origin of species, Lamarckism tackled the more difficult question of the origin of variation. He cited two reasons for considering

Darwinism a more productive biological theory than Lamarckism: first, it operated within a narrower frame of reference, which helped it avoid "unanswerable questions"; and second, it had no need for assuming the existence of an inscrutable innate drive that renders evolution an ordered progress.

While hailing the possibility and necessity for at least a partial fusion of the Darwinian tradition and the new branches of experimental biology, Kholodkovskii refused to accept neovitalism as a stream of thought contributing to a grand synthesis of biological thought. In this respect, he acted as a true representative of unorthodox Darwinism. In the 1890s, he thought, neovitalism offered the most belligerent and sustained opposition to Darwinism as a general and comprehensive interpretation of the natural mechanism of organic evolution. He contended that the strongest neovitalist opposition to Darwinism came from Hans Driesch. Unlike Eduard Hartmann, who defended neovitalism from metaphysical positions, Driesch was a respectable scientist who, at one point in his career, decided to widen the cognitive horizons of biology by employing neovitalist tools. He borrowed the Aristotelian notion of entelechy to describe the essential powers that separate life from the inorganic world and to help in understanding the purposiveness of the vital processes. Kholodkovskii gave Driesch's ideas a fair airing in Russia, but he also joined a large group of biologists who opposed every "metaphysical" interference with biological thought. Teleology, according to Kholodkovskii, is a "philosophical notion," and natural scientists must treat it as "unnecessary" and "useless."^[12] His firm opposition to neovitalism helped create a firmer base for his dedicated search for closer functional ties between Darwinism and burgeoning genetics.

The second—and most distinguished—representative of unorthodox Darwinism was I. I. Mechnikov. He, too, recognized not only the fundamental "correctness" of Darwin's theory but also the need for widening its empirical and theoretical base. Evolutionary theory, as he interpreted it, needed more than the mere addition of details to Darwin's views: it needed new and more precise perspectives in the study of heredity, variation, and psychological adaptation. Mechnikov worked within a broad framework of evolutionary thought: his research and publications covered comparative embryology, comparative pathology, the theory of evolution, the history of biology, and the relations between biological evolution and social change.

During the entire course of his scholarly career, Mechnikov wrestled with the problem of evolution in general and with the Darwinian theo-

retical legacy in particular. His position was generally clear: he accepted evolution as the key to a true understanding of the structure and the processes of life, but he contended that no evolutionary theory—not even Darwin's—could explain by itself all the key aspects of evolutionary dynamics. Darwin's theory, he maintained in 1871, cannot claim the attribute of universality, for there are many aspects of the evolutionary process that it cannot account for. For example, it cannot explain why, in rare cases, "very similar" animals, living under the same environmental conditions, undergo different transformations.^[13] Nor can it explain how the numerous species of the phylum Nematoda can preserve the same body organization even though they live in a wide variety of environments.^[14]

At first Mechnikov concentrated on studies in comparative embryology: many of his objects of inquiry belong to the rich fauna of the Mediterranean Sea. It was also at this time that he developed a habit of writing critical surveys of current developments in zoology. His doctoral dissertation, which earned him academic employment at the University of Odessa, dealt with the embryonic growth of the crustaceans. During the 1870s Mechnikov continued to work in evolutionary embryology, but he also tried to reach a wider audience with popular discourses on the questions of evolution that he found most puzzling and, at the same time, most important for the formulation of the basic principles of a historical view of the living universe. A perceptive historian of science, he now tried to elucidate the intellectual roots of the notion of biological evolution. He confronted the question of evolution outside the traditionally defined domain of biology. The riddle of the sociological meaning of the struggle for existence as an evolutionary mechanism of human society did not escape his serious consideration, nor did he overlook the complex relation between the biological causation of conflict and the moral imperative of cooperation. While he did not completely rule out conflict as a mechanism of social evolution, he had little use for Malthus's demographic formula. He also wrote about the complexities and dilemmas of extending Darwinian evolutionism to the domain of anthropology, at the time one of the most rapidly developing disciplines. All these writings carried the same message: "Science commands so few facts on the struggle for existence that . . . it is forced at every step to rely on indirect proofs and logical deductions."^[15] Still, he missed no opportunity to remind his readers that, despite its glaring imperfections and need for extensive recasting, Darwin's theory was more promising than any other transformist theory.

During the 1880s Mechnikov's identification with Darwin's theory became stronger and more direct. The gradual solidification of his allegiance to Darwinism appeared at the time of his growing engagement in work on the phagocytic theory of inflammation and, in general, on the embryological foundations of evolutionary pathology. He presented the struggle between pernicious bacteria and protective phagocytes as a special case of the universal struggle for existence.^[16] Mechnikov devoted much attention to explaining the adaptive mechanisms of phagocytes and bacilli during various phases of the ongoing war.

Phagocytic reactions, as intracellular defense mechanisms, are much older than secretions of extracellular antitoxins, at least according to Mechnikov. By injecting toxins into various animals, he claimed to have established that invertebrates were incapable of producing antitoxins, an activity that begins with reptiles.^[17] Mechnikov drew an evolutionary conclusion about the phagocytic defensive reactions: they are both the oldest and the most basic mechanisms for protecting multicellular organisms from pernicious bacilli. He claimed that the comparative-evolutionary method unveiled not only the general characteristics of inflammation that are shared by animals and human beings, but also special characteristics, representing evolutionary stages and growing complexities of animal organization. His effort to place immunology into an evolutionary framework was a bold effort to carry Darwin's theory to a new field of biological research. He wrote at the end of the century: "The phagocyte theory, based on the principles of Darwin's and Wallace's transformism, can serve as a particular basis for the study of the organic world. [By studying inflammation] we participate, as it were, in a struggle and observe natural selection at work."^[18]

In 1916 Mechnikov received the Albert Medal of the Royal Society of Arts, an English learned body, for his scientific achievement. The citation placed a particular emphasis on his work on phagocytes—and on the nature of immunity to infectious diseases. It noted that his observations of the activity of the mesoderm cells in the embryonic organs of echinoderms led to the knowledge that "the white blood-cells of phagocytes devour the invading microbes in vertebrates also," thus showing "the universal applicability of his generalization."^[19] The citation stated that Mechnikov had contributed to the control of infectious diseases "more than any other living being." It was this achievement that earned Mechnikov the Nobel Prize in 1909—which he shared with the German pathologist Paul Ehrlich—and the Copley Medal of the Royal Society of London.

As Mechnikov saw it, Darwin's theory of organic evolution made a strong impact on medicine. "Illnesses," he wrote, "which are not an exclusive privilege of mankind or of a limited number of higher animals, are regulated by the great laws Darwin had discovered. The recognition of this truth has laid the foundations for comparative pathology, a branch of biology concerned with pathological processes that take place in all the phases of the entire organized world."^[20]

Triumphant in his scholarly achievement and deeply involved in elaborating a philosophy of "rationalism," Mechnikov was now inclined to be much more direct and categorical in recognizing the revolutionary sweep of Darwin's theory of evolution. In 1909 he was among the noted scientists who gathered in Cambridge to observe the one-hundredth anniversary of Darwin's birth and the fiftieth anniversary of the publication of the Origin of Species . In a short speech at the celebration he noted that Darwin's theory made it possible for pathology to reap bountiful harvests from an evolutionary approach.^[21] In a summary of the main points of his speech, Mechnikov noted:

The truth that man is a blood relative of the animal world has become the basis of comparative pathology. With the help of the study of lower organisms it has become possible to prove that inflammation is not a manifestation of illness, but a reaction of an organism to pathogenic activities. The theory of the origin of species offers suggestions for the study of the most difficult problems of medicine, among which the questions of malignant tumors (cancer and sarcoma) occupy the first place. Medicine has no room for the assumption that. . . . tumors develop from faulty starts of germ layers. On the contrary, Darwinism has shown that among lower animals that develop from germ layers tumors are always caused by parasites, which suggests a similar origin of cancerous tumors among men.^[22]

E. Ray Lankester had no difficulty in detecting a strong strain of Darwinism in the phagocyte theory. He pointed out that "inflammation, as a creative process, depended on special mechanisms established by natural selection." He viewed the "Struggle of the Organism against Microbes," Mechnikov's initial report on phagocytes, as an evolutionary study guided by Darwin's ideas. The phagocyte theory, he wrote, was a major step in the advancement of modern medicine.^[23]

While enriching many disciplines, Darwin's theory acquired a broader and firmer empirical support.^[24] It also acquired a more precise and complete conceptual structure. In Mechnikov's view: "While it is correct to state that many points of the theory of evolution have not yet been fully explained, it is perfectly obvious that the foundations Darwin had built

can be regarded as fully established."^[25] This assertion, however, did not make Mechnikov a champion of Darwinian orthodoxy. Unlike Timiriazev, he welcomed the new developments in the experimental study of heredity and variation and readily accepted the possibility of a cross-fertilization of various theoretical orientations in evolutionary biology. He openly criticized "the purveyors of orthodoxy who would have us believe that science has made no progress since the time Darwin published his works." "Orthodox Darwinists," he wrote, "do not recognize the incontrovertible fact that changes in living forms are sometimes sudden leaps that skip intermediate phases."^[26]

The Darwinian commemorative sessions in 1909 at Cambridge University helped strengthen Mechnikov's admiration for Darwin's scientific contributions. They also convinced him that Darwin's legacy could only be strengthened by a refashioning of its basic principles in the light of the evolutionary ideas advanced by experimental biology.^[27] He was much impressed with de Vries's mutation theory, but never before was he closer to Darwin's ideas on the evolutionary role of the struggle for existence and natural selection. He viewed Darwin's theory as a turning point in the history of modern science, but he publicly chastised E. Ray Lankester for his attack on de Vries's mutation theory and on "Bateson's research in heredity based on Mendel's theory."

During the closing decades of his active engagement in scholarship, Mechnikov relied on Darwin's ideas as the most comprehensive and most viable evolutionary theory of his age. He treated Darwin's theory as a rich source of suggestions for reconciling and unifying the apparently discordant theoretical products of many branches of experimental biology. By taking Darwin's principles to a new realm of inquiry, he helped establish comparative pathology as a distinct discipline. Darwinian thought occupied the central position in his world outlook, based on a firm conviction that the growth of rationalism was the most significant index of cultural progress. A true Darwinist, he found no use for neovitalist inroads into biological thought.^[28]

Vladimir Mikhailovich Shimkevich was a professor of zoology at St. Petersburg University.^[29] His enormous scientific output dealt primarily with the morphology, embryology, and systematics of a wide representation of invertebrates, many from the phylum Arthropoda. Particularly noted were his studies of the embryonic development of individual organs or complexes of functionally related organs. Together with his assistants at St. Petersburg University, he made a sustained effort to combine advanced techniques of observation with experimental re-

search. At the end of the nineteenth century the zoological laboratory at his university was known as the most advanced Russian center for experimental study of organic evolution. Shimkevich earned wide reputation for his essays in biological theory and for his critical surveys of current developments in the leading branches of experimental biology.

From the beginning to the end of his active engagement in scientific work, Shimkevich was a loyal supporter of Darwin's theory. In the 1890s—before the emergence of de Vries's mutation theory and the revival of Mendel's theory of heredity—he was happy to see Darwinism not only as a culminating point in the history of evolutionary ideas but also as an inexhaustible source of research perspectives. He wrote: "All research activity in embryology, comparative anatomy, and paleontology of the post-Darwin era consists of efforts to meet the goals stated in Darwin's legacy. Darwin lived to see the evolutionary theory, built on biological facts, become part of sociology, linguistics, and, finally, philosophy."^[30] The future of biology, as Shimkevich saw it in the 1890s, lay in building upon the basic principles of Darwin's theory. This did not stop him from welcoming research in the mysterious world of heredity. In an essay dealing with the Spencer-Weismann dispute he looked optimistically at the ongoing engagement of experimental biology in the microscopic study of the molecular processes of heredity.^[31] He reasoned that this branch of biology would start a new phase in the history of evolutionary thought.

During the early years of the twentieth century, Shimkevich conceded that the future of evolutionary biology lay in broad and progressive adjustments of Darwinism to the ideas of various new trends in experimental biology. At no time, however, did he abandon his firm conviction that Darwin's theory was the foundation of modern biology. Relying on a dispassionate style of writing and on cautious analysis, Shimkevich gave support to an orientation that saw the future of biology in clustering modern theoretical advances around a core of Darwinian thought. Although he favored the Darwinian side of the evolutionary equation, Shimkevich was ready to treat the Mendelian theory of heredity and de Vries's mutation theory as fundamental components of a general theory of organic evolution. While interpreting Weismann's views on heredity as a revival of the theory of preformation, he anticipated the search for a meeting point between epigenesis and preformation to occupy a central position in the future development of genetics. He warned, however, that the problems of epigenesis were much more accessible to experimental study than were the problems of preforma-

tion.^[32] The Biological Foundations of Zoology, his major university textbook, introduced students to the intricacies of Mendelian laws.^[33] It also presented the mutation theory, analyzing both its strengths and its alleged weaknesses.^[34] The textbook gave a limpid and accurate account of Korzhinskii's and de Vries's theoretical views. Shimkevich played a major role in resisting Timiriazev's campaign to slow down the flow of ideas generated by modern genetics through the channels of scientific communication.

In an effort to unify Darwin's and de Vries's evolutionary views, Shimkevich preferred to divide all heritable characters into three categories: those that emerged suddenly, those that emerged gradually, and those that emerged either suddenly or gradually. In a special study he tried to show that the most pronounced mutations belonged to the realm of teratology. He thought that generally there is no fundamental difference between Darwin's "slight modifications" and de Vries's "mutations" except that individual species prefer one or the other method. At one time he thought that mutations are not a reality sui generis, but a specific kind of Darwin's variations.^[35] Not questioning the reality of mutations, he was inclined to view "slight modifications" as the most common mode of transformation in the organic world.^[36]

Despite his generally favorable outlook on current developments in experimental biology, Shimkevich protected Darwinism from basic criticism. He fought against "repeated efforts" in contemporary Russia to discredit the struggle for existence as a factor of evolution without taking note of the full spectrum of meanings Darwin attributed to it. "Every biologist knows," he wrote, "that the word struggle denotes not only rivalry, in the strict meaning of the term, but also a predatory mode of life, passive defense, and resistance to external agents—briefly, an entire network of complex relations that determine the survival potential of plants and animals."^[37] He made no effort to minimize the role of the struggle for existence as one of the prime movers of human society.

Darwinism, according to Shimkevich, had three particularly strong scientific assets: it was firmly anchored in empirical knowledge; it offered promising perspectives for new research; and it received strong support from the history of biological thought. A typical Darwinian scholar at the beginning of the twentieth century dealt exclusively with the first two assets. Shimkevich belonged to the small group of biologists who studied the history of their discipline with the explicit purpose of presenting Darwinism as a high point in the gradual growth of evolutionary thought.^[38]

In his university textbook on zoology and comparative anatomy, Shimkevich expressed an unwavering allegiance to the cause of Darwinism. At a time of trial and crisis in evolutionary thought, this book helped reinforce and consolidate Darwinian tradition in Russia. It helped soften the pressure generated by various new orientations that either challenged Darwin's basic principles, such as natural selection, or gave "unexpected" answers to questions Darwin raised but did not answer, particularly in the domains of variation and heredity.

Shimkevich acted as a consistent defender of Darwinism, regardless of the source of attack. In 1901 the Ministry of Public Education ordered secondary public schools to emphasize anti-Darwinian views in teaching the life sciences. Shimkevich joined a group of educators who appealed to the authorities to rescind the ordinance and who received a relatively favorable response to their plea.^[39]

Shimkevich occupied a borderline position between the defenders of Darwinian orthodoxy and the defenders of unorthodox views. He deserved to be identified as an unorthodox Darwinist because he recognized that Darwinism must find a way to coexist with the great discoveries that made genetics one of the most progressive biological disciplines. Moreover, he played a major role in drawing the attention of both the scientific community and the general public to the new biological disciplines. On occasion, however, Shimkevich acted more as an orthodox Darwinist. In some papers, he interpreted the contributions of Mendel and de Vries in such a way as to make them fit into a larger pattern of Darwinian thought. He made no systematic or sustained effort to accommodate Darwin's theory to the demands of the more recent developments in evolutionary thought. One is often left with the impression that he was concerned much more with protecting Darwinism from the heretical ideas unleashed by genetics than with proposing a working synthesis of the two strands of evolutionary thought.

The list of noted biologists who supported Darwinism but opposed Darwinian orthodoxy and who contributed to the search for a more comprehensive theory of organic evolution should also include Valerii Ivanovich Taliev. A docent at Kharkov University from 1900 to 1919 and then a professor at the Moscow Agricultural Academy, he worked in several fields but was particularly noted for his studies in botanical geography and the theory of evolution. His most important contributions to botanical geography included volumes on the plant life in Kharkov province and in Crimea, enriched by a systematic analysis of the influence of human activity on the succession of vegetation covers

and on the impoverishment of soil.^[40] He added fresh insights to the strong interest of Russian botanists in the evolution of "plant communities," or "plant associations," in S. I. Korzhinskii's terminology. The biotic process responsible for transforming dense forests into marshland, on the one hand, and into rocky steppe, on the other, attracted much of his attention. He helped inaugurate a systematic study of the ecological effects of combined natural and artificial selection.

Taliev likened Darwin to a mountain stream. Tumbling down the precipitous gorges, a mountain stream destroys everything that stands in its way and absorbs numerous little creeks along its course. Once it reaches the flatland the stream becomes a river, rich in water but without mountain stimuli to give it the power to crush all the obstacles it encounters. As a mountain stream, Darwinism, bursting with power, destroyed every opposition, partly by converting enemies into supporters. At the end of the century it had become a river, large in size but too sluggish to sweep away the mounting challenges from unfriendly critics.^[41]

In assessing the strengths of Darwinism Taliev was guided by two premises. First, he gave Darwin full credit for making one unchallengeable contribution to modern biology: he "completely destroyed the notion of the immutability of species and replaced it with the fertile idea of evolution, making it a solid basis of modern science."^[42] Second, all Darwinian evolutionary principles must be reexamined and reassessed in the light of new empirical evidence and theoretical insights. Such questions as variation and heredity, whose formative processes and mechanisms Darwinism did not broach with sufficient vigor and determination, must be given high priority in evolutionary research. The time had come for Darwinism to reconcile or blend its theoretical principles with those of modern evolutionary theories that grew outside—and often in direct opposition to—the Darwinian tradition.

In "Biological Ideas during the Second Half of the Nineteenth Century," published in 1900—before the resurrection of Mendel's theory and the emergence of de Vries's mutationism—Taliev concentrated on the most common challenges to Darwinism, particularly during the 1890s. Whether he discussed the teleological and panpsychic orientation of neovitalism, the neo-Lamarckian defense of the idea of the inheritance of acquired characteristics, or the neo-Darwinist negation of any role of the environment in generating heritable variation, his primary interest was to survey the basic questions that a modern theory of evolution could no longer ignore. His analysis made it clear that neovitalism, neo-Lamarckism, and neo-Darwinism were successful in pointing out a

number of critical problems that required a reorientation in biological thought, but not in providing satisfactory answers. The time had come, he said, for the formation of new approaches to the compounded dilemmas of evolution, particularly in the domain of heredity. He was optimistic that the time for new Darwins would come in the near future.^[43]

At this time, Taliev sensed that the new evolutionary theory would depend on Spencer's ideas to build a bridge between Darwinism and various branches of neo-Lamarckism, and on Weismann's ideas as a link between Darwin's thought and the swelling streams of scientific knowledge that led to the founding of genetics as a distinct discipline. In his opinion, the future of the theory of evolution belonged to the study of heredity, which in turn concentrated on both internal and external sources of heritable characteristics.

Taliev returned to the idea of organic evolution in several studies.^[44] In 1902 he published an essay entitled "On Purposiveness in Nature" in which he elaborated his criticism of the ideological orientation of neovitalism and defended Darwin's interpretation of purposiveness in the organic world as a factor operating strictly within the scope of natural causation.^[45] In 1907 he published Lectures on General Botany, the first Russian university textbook to be cast completely within an evolutionary framework.

In December 1909 Taliev read a paper, "Darwinism, Lamarckism, and the Theory of Mutations," in which he acknowledged "the broad scope of the revolution in science wrought by Darwinism."^[46] He rejected de Vries's alleged effort to transform the mutation theory into a general biological theory, but he was ready to admit that the idea of "saltatory variation" was a strong addition to the theory of evolution and that it introduced an "important corrective" into Darwin's theory of slight modifications. He added that mutations are not the only source of variation. Future research, he said, should illumine the role of the changing environment—a Lamarckian factor—in making mutations part of a progressive process in the evolution of the forms of life. He tried to harness both mutationism and Lamarckism in support of Darwinism as a general theory of evolution.

Taliev's doctoral dissertation, A Study of Speciation in Living Nature, defended at St. Petersburg University in 1915, was actually a collection of essays grounded in empirical research and concerned exclusively with the theory of organic evolution. Now he was clearly less optimistic about the promise of genetics. At the very beginning of the study, he announced that he found experimental biology a rather lim-

ted source of information on the development of species.^[47] He admitted that he found the research based on the mutation theory particularly wanting. Nor was he favorably disposed toward the rapidly growing Mendelian research. In his opinion, organic evolution is such a slow and intricate process that for a long time it will continue to be beyond the reach of the experimental method. Instead of the experimental method, he opted for the "comparative-morphological" inquiry, the Darwinian method, as the main source of data for his essays.

Taliev did not ignore the mutation theory altogether. He thought, however, that it could be used most profitably as an integral component of a larger complex of Darwinian thought. He also thought that the difference between Darwin's minute modifications and de Vries's mutations were more in semantic interpretation than in naked reality. Mutations, like natural numbers, could be interpreted either as discontinuous (discrete) phenomena or as units of continuous processes.^[48] Darwin did not exclude "leaps" (or "sports") from his view of organic evolution as a continuous augmentation of minute modifications. In general, Taliev stuck to the view that evolution is a result of "infinite changes in existing variations."^[49] Not mutation as a discontinuous change outside "existing variations," but the continuous and ever-deepening process of fission within "existing variations," is, in Taliev's view, the primary wheel of evolution. He was ready to admit, however, that the acceptance or rejection of the mutation theory must wait for more systematic and thorough testing.

Along with Tsinger's work on the false flax (Camelina linicola ), Taliev's study of speciation was the only empirical study in Russian botany devoted in its entirety to the problems of evolution. Although he thought that "the evolutionary theory has become the meeting ground of all branches of biology,"^[50] he was not sure that experimental genetics was an evolutionary discipline in the first place. In fighting mutationism, in particular, he fought Korzhinskii much more than de Vries, for it was Korzhinskii who relied on the theory of heterogenesis to conduct an open war on Darwinism. In his references to Mendel and Mendelism Taliev was more fragmentary but equally unreceptive. Endorsing Timiriazev's attack on Western scientists who tended to "exaggerate" the contributions of genetics, he argued that Mendel's approach to heredity substituted "algebraic schemes" for "an analysis of concrete factors."

His pronounced skepticism about the usefulness of Mendel's and de Vries's contributions did not mean that Taliev had decided to fall back into the fold of Darwinian orthodoxy. It meant only that he looked in

other directions for theoretical and methodological ideas that could inject new blood into the Darwinian tradition. For example, he used every opportunity to suggest the need for exploring the avenues of cooperation between Darwinism and Lamarckism. Several times he returned to the idea of evolution as a process of orthogenetic adaptation, which came out of the Lamarckian tradition. Darwinism, he thought, needed a toning down of its exaggerated emphasis on the struggle for existence and natural selection as mechanisms of evolution. It should also join the modern efforts to study organisms as physicochemical systems.

Taliev's book received wide attention in Russia. The Nature reviewer objected to its negative attitude toward the mutation theory and to its heavy dependence on Darwin's theory of the divergence of characters.^[51] In the newly established Journal of the Russian Botanical Society, V. L. Komarov criticized the author for disregarding Mendel's theory of heredity, itself not without imperfections.^[52] The main criticism came from R. E. Regel' in a twenty-four-page review in the Proceedings of the Bureau of Applied Botany .^[53] Regel' obviously used the opportunity not only to provide a detailed rebuttal of Taliev's methodology and theoretical criticism but also to explain the basic principles and recent achievements of genetics. The review marked the first systematic and comprehensive effort in Russia to mount a counteroffensive against the foes of Mendel, de Vries, and their followers. Regel' pointed out that to study the process of speciation by disregarding the vast resources of genetics was to ignore some of the most dramatic achievements of modern biology. He made it clear, however, that he was far from claiming perfection for all information that genetics had produced. His critique of Taliev's work gave Regel' a splendid opportunity to make up for the sin of early geneticists: instead of harping on the alleged flaws in Darwin's thinking, he admitted that the foundations which Darwin placed under biology had continued to be indestructible.^[54]

The supporters of unorthodox Darwinism, represented by Kholodkovskii, Mechnikov, Shimkevich, and Taliev, were remarkably consistent in their general views on the major theoretical orientations in modern biology. All recognized the vast potential of Darwinism as the fundamental framework for evolutionary theory. All expressed a firm conviction that Darwinism must come to terms with the new ideas in biology, not by abandoning its guiding principles but by making them more flexible and less authoritative. Although they were not always judicious in presenting the relative strengths and weaknesses of competing theories, they helped open the gates for new concerns and ideas in evo-

lutionary biology. They agreed with Lamarckism on the powerful role of environment in the evolutionary process, but they contended that no empirical evidence supported direct influence of the external environment on the transformation of species. Shimkevich was not alone in acting as if he would not be surprised if future research produced evidence in favor of such an influence, at least on a limited scale. In one of his major papers on heredity, he talked much more extensively about the Lamarckian experiments conducted by Standfuss, Przibram, and Kammerer than about the achievements of genetics.^[55] No unorthodox Darwinist saw the possibility for fruitful cooperation with psycho-Lamarckism, represented by Raoul Francé and August Pauly in Germany. Nor did they envisage any points of contact with neovitalism.

Darwinism and Genetics

In addition to unorthodox Darwinists, there was another group of biologists who exercised a strong influence on the development of Darwinism at the beginning of the twentieth century. This group consisted of scientists who labored in the new field of genetics. While unorthodox Darwinists were strongly inclined to look at the leading ideas of genetics from Darwinian positions, the geneticists preferred to look at Darwinism from the theoretical heights of their discipline. Both groups saw the future of evolutionary biology in a combination of Darwinian heritage and the ideas of genetics and related branches of experimental biology.

At the beginning of the twentieth century, two capital developments in experimental biology—the mutation theory and the rediscovery of Mendel's laws of heredity—laid the foundations for the emergence of genetics, a new science involved in the study of two cardinal aspects of organic evolution: variation and heredity. The representatives of the new discipline presented a vigorous challenge to Darwin's theory of organic evolution. But they also inspired a sustained search for a working reconciliation of Darwin's evolutionary views with the new theoretical insights. Only to isolated interpreters in the changing panorama of biological thought did the new theories appear as harbingers of an irreversible collapse of Darwinian thought.^[56] One such interpreter was Evgenii Shul'ts, who favored the experimental method of the new biology over Darwin's emphasis on observation and was impressed with Hans Driesch's neovitalism. He anticipated that "the new biology" would move away from historicist orientations in biology, which, in his

view, made it exceedingly difficult to design research methods capable of producing reliable empirical data.^[57] Representing an isolated position in Russian biological thought, Shul'ts made no serious effort to elaborate his antihistoricist arguments.

In 1899 S. I. Korzhinskii published a paper entitled "Heterogenesis and Evolution" in which he presented an extensive survey of examples illustrating what he thought to be the key role of saltatory changes—or "sudden divergences"—in the origin of species.^[58] He anticipated the mutation theory, Hugo de Vries's bold new step in the development of biological evolution. Indeed, Korzhinskii provided the first systematic and elaborate effort to advance and systematize the mutation theory. He died in 1900, before he had completed the second—theoretical—part of the study. Korzhinskii did not base his study on his own empirical—or experimental—work; he merely went through a mass of literature in search of illustrative material for his thesis. The collected material convinced him that there were two categories of change in organic nature: gradual change producing variation within the type, and heterogenetic change, made of drastic deviations, leading to the formation of new types.^[59] Heterogenetic changes, in Korzhinskii's view, are fully independent of, and are not induced by, the external environment, and they are hereditary. He admitted, however, that he was in no position to identify the internal causes of saltatory changes. Heterogenesis produced both "progressive" and "regressive" evolution. The mechanism of evolution is mainly what Darwin said it is not. Korzhinskii gave his theory of heterogenesis a clear and direct explanation:

Regardless of what their real causes may be, heredity and variation are two forces hidden in the organism; they are two tendencies in a state of mutual antagonism. Under normal conditions—that is, in races that are well established and unimpaired—heredity has absolute power in producing identical generations. Variation, by contrast, is not continual. During many generations it must, so to speak, gather energy for the purpose of overcoming the power of heredity and of giving birth to new races.^[60]

One year after Korzhinskii's death, Hugo de Vries published the first volume of The Mutation Theory, based on extensive and prolonged experiments with Oenothera lamarckiana, which provided a full confirmation of Korzhinskii's theory of heterogenesis and was quickly recognized as a turning point in the history of evolutionary thought. De Vries acknowledged the universality of Korzhinskii's heterogenetic interpretation of speciation and view of natural selection as a "conservative process," which preserves the existing forms and prevents further

changes.^[61] Almost paraphrasing Korzhinskii, he asserted that there are two types of variation—"individual" and "mutational"—which are fully independent of each other, and that only mutational variation can overstep the species limits.^[62] De Vries did not try to minimize Darwin's contribution to modern biology; he merely chose to place strong emphasis on one of the factors of evolution which did not attract Darwin's primary attention. This did not prevent him from giving Darwin credit for making organic transformation the major subject of empirical study in biology.^[63] He supplied anti-Darwinists with new ammunition, but he refused to join the anti-Darwinian movement.

Mutationism, in brief, challenged Darwin's theory on three grounds. First, Darwin claimed that the continuous acquisition of minute variation is the natural process of speciation; Korzhinskii and de Vries recognized only discontinuous or discrete leaps or mutations as the sources of new species. Mutationism rejected not only Darwin's canon of natura non facit saltum but also the mechanical law of the continuity of motion, the paramount principle of Newtonianism. De Vries's strong emphasis on discontinuity in evolutionary processes took place in the same year that Max Planck discovered the discontinuity of black-body radiation. Second, while Darwin placed the primary emphasis on the struggle within the species, the mutationists emphasized the struggle between the species. Third, Darwin viewed natural selection as a positive process leading to the origin, development, and perfection of species; de Vries and his followers viewed it as a negative process—a process that destroys species burdened with inadaptive mutations. Outside the scientific community, mutationism was widely regarded as a total denial of Darwinism, and because of its formal semblance to creationism it was widely heralded by theological writers.

Most Russian Darwinists welcomed the new theory, but they also voiced strong reservations. A typical critic made it known that de Vries incorporated two Darwinian ideas into the mutation theory: the struggle for survival and natural selection.^[64] Most biologists accepted mutation as a source of new species, but they tended to treat it merely as a minor factor of the evolutionary process. The mutation theory, they thought, complemented, rather than contradicted, Darwin's theory. When de Vries conceded that the struggle for existence determined which mutations would survive, he received commendations from many Darwinists, even though he made little effort to elaborate his views.

In 1903 O. V. Baranetskii, a well-known plant physiologist from Kiev University, published a lengthy review of several recently published

studies critical of Darwin's theory, including Korzhinskii's "Heterogenesis" and de Vries's Mutationstheorie . He noted that organic evolution, as Darwin portrayed it, "occupies the same place in history that axioms occupy in mathematics." Current "criticism," he said, was directed not at evolution but at various misinterpretations of its inner mechanisms.^[65] By implication, Korzhinskii and de Vries did not deny the "axiom" of evolution but gave it a more precise and accurate interpretation. A scrupulous analysis of the new ideas did not prevent Baranetskii from concluding that the idea of evolution continued to be unclear and imprecise. From Darwin to de Vries, he said, the biologists had been busy trying to reduce the evolution of life to a "material substratum"—to explain the laws of organic nature in terms of the laws of inorganic nature. Baranetskii sided with "the growing number of serious scholars" inclined to recognize a special vital principle that explains the most fundamental characteristics of life.^[66] He was not sure, however, that "the natural course of scientific progress" would lead to the triumph of this principle.

Commentators on the relationship of new developments in experimental biology to Darwin's theory followed many lines of reasoning. Most of them occupied a position somewhere between full acceptance and full rejection of the complementary roles of mutationism and Darwinism. Baranetskii, for example, hinted that Darwin's and de Vries's theories of evolution were not comparable empirically and operated at different levels of abstraction. While de Vries, in his opinion, operated with "critically" examined and precisely established empirical facts, Darwin operated with data that were not adequately authenticated. De Vries's theory is an empirical generalization; Darwin's natural selection is a "theoretical construction," devoid of a solid empirical base. De Vries, however, had much more difficulty in staying within the realm of natural causation in interpreting mutations as factors of organic evolution. Darwin's random variations are "slight" and occur in endless profusion; de Vries's "random mutations" represent drastic changes and occur very rarely. For these reasons, Baranetskii argued, it is much easier to accept natural selection as a mechanism of evolution. Darwin's theory retained its popularity because it did not transgress the boundaries of natural causation. It preserved its authority because it offered "simple" and "logical" explanations.^[67] This did not mean, however, that it did not require major improvements. In general, Baranetskii considered both theories imperfect. What biology needed, in his opinion, was a general principle that could explain all the manifestations of life.

He was obviously under the spell of the proliferating neovitalist literature. This did not stop him, however, from considering de Vries's theory the beginning of a new era in biology.

A. S. Serebrovskii admitted that de Vries's mutation theory contradicted Darwin's views on the mechanism of evolution; he noted, however, that the new theory harbored too many ambiguities and uncertainties to present a serious threat to Darwin's ideas.^[68] Unlike Timiriazev, he voiced a generally optimistic view of the future role of the mutation theory in the development of evolutionary biology. The future, he said, belongs to the harmonizing of "progressive mutations" with "progressive evolution."

At first Korzhinskii's and de Vries's theories received only perfunctory attention in Russia: they attracted attention more as challenges to Darwin's theory than as new designs for empirical research. Their departure from Darwin's theory was so radical that most biologists required time to digest their basic research implications. Korzhinskii attracted wide attention in Russia primarily as a critic of the mechanistic foundations of the evolutionary theory.^[69] Timiriazev, Menzbir, Taliev, and other Darwinists expressed particularly strong criticism of his views that brought him close to neovitalism. The critics of Darwinism, typified by I. P. Borodin and A. S. Famintsyn, were pleased with Korzhinskii's antimechanistic stance. The first generation of Russian geneticists, represented by Regel' and Filipchenko, wasted no time in recognizing Korzhinskii as a true pioneer of the "new biology."

Neo-Darwinism and mutationism made the rediscovery of Mendel's theory, presented and promptly forgotten in 1865 and 1867, an unavoidable event. The rediscovery of Mendel's scientific legacy in 1900 marked a high point in the growing effort to give the evolutionary theory an experimental base. William Bateson, who coined the term genetics in 1906, deserved the major credit for placing the new science on two pillars: Mendelism and mutationism. Mendelism showed that all normal variations resulted from mathematically predictable combinations of the particulate units of heredity. Mutationism showed that all "unexpected" variations came from internally caused and sudden "leaps" in the makeup of the cytological base of heredity. The new science challenged the two basic principles on which Darwin's theory was built: Mendelism challenged the interpretation of evolution as a random process; the mutation theory challenged the idea of evolution as a gradual process. The new biology agreed with neo-Darwinism in rejecting the notion of the inheritance of individually acquired characteristics as a

factor of organic evolution. It differed from neo-Darwinism in rejecting the notion of natural selection as a primary mechanism of evolution.

The generally cautious reaction of Russian biologists to Mendel's theories was far from uniform. In 1903 the popular journal God's World (Mir bozhii) gave a clear presentation of Mendelian laws and expressed a guarded view of their future role in the development of the theory of organic transformation.^[70] Despite his enthusiastic endorsement of Mendel's ideas, I. P. Borodin, the author of the article, thought that they did not present a universal law of nature.^[71] Nor did he hide his skepticism about de Vries's emphasis on mutation as the prime mover of organic evolution.^[72] He devoted much more space to spelling out the substance and the logic of the new theory than to giving his criticism more depth and precision. The article carefully avoided references to the specifics of Darwin's theory. In the third edition of his textbook The Biological Foundations of Zoology, V. M. Shimkevich devoted a special section to a careful summary of Mendel's theory.^[73] M. A. Menzbir's textbook on zoology and comparative anatomy made no mention either of Mendel or of his theory.

In 1909 N. Iu. Zograf, a Moscow University professor, produced a Russian translation of Experimental Zoology (1907) by Thomas Hunt Morgan. The translated work was a welcome addition to the growing literature on the state of the new biology. This was the first serious scholarly work to give a critical review of salient developments in experimental biology during the first decade of the twentieth century. It summarized the strong empirical arguments against the Lamarckian theory of the inheritance of acquired characteristics. It presented the points of contact between Mendelism and mutationism as a most promising prospect for the future development of evolutionary biology. Morgan admitted that the complexity of the process of evolution made it imperative to exercise extreme caution in relating the new stirrings in biology to Darwinism. To survive as a viable scientific theory, Darwinism, in Morgan's view, must take into account the new developments in experimental biology. He thought that Darwin made his theory so general that it could easily be interpreted as covering de Vries's view on the role of mutations in the evolutionary process.^[74] All this did not mean that Morgan accepted Mendel's and de Vries's views without criticism. In current developments he saw the beginning of a new science, which would give Darwin's theory more precision and broader latitude. Implied in Morgan's arguments was the idea that, in order to realize its potential, the Darwinian notion of evolution must be modified in the light of new

advances in science. The main value of Morgan's volume was in recording the questions that must be answered before the theory of organic evolution could be raised to a higher level of scientific abstraction.

Thanks to the energetic and realistically ambitious efforts of R. Regel', the Bureau of Applied Botany became the first Russian center of genetic research. In "Selection from a Scientific Point of View" (1912), Regel' offered a long and sympathetic discussion of the new frontiers of knowledge opened by the Mendelian laws.^[75] He looked forward to a future synthesis of different strands of evolutionary thought. In his view: (1) mutations are the only source of primary—nonderivative—hereditary characters; (2) Mendelian laws show that the external environment cannot alter hereditary characters and that, under normal conditions, only the crossing of different races can produce secondary—derivative—variability; and (3) the struggle for existence alone determines which of the new combinations have a survival potential. "Scientific breeding," according to Regel', depends on a functional interdependence of organic processes described by de Vries, Mendel, and Darwin. In all this, the struggle for existence is strictly a conservative factor; it contributes to the preservation of living forms adapted to the environment.^[76]

It is fair to say that to Regel', as to Darwin, evolution depended on three basic factors: variation, heredity, and natural selection. It is equally fair to say that he gave these factors a more modern explanation, placing a particularly strong emphasis on such achievements of modern experimental biology as Mendel's laws of heredity and de Vries's mutation theory. Although he used every opportunity to pay homage to Darwin, he dealt primarily with the contributions of genetics to the study of transmission and combination of hereditary factors. He worked hard to neutralize the current inclination of the new biologists to consider genetics an anti-Darwinian branch of biological knowledge. Regel' went so far as to claim that the notion of "species" is too ambiguous to serve as the basic taxonomic unit and that it should be replaced by a new unit, which he identified as "race" or, following de Vries, as "elementary species," based on the genetic criteria of Mendel's laws.^[77]

In his appraisal of the general factors of evolution, Regel' noted the basic differences between Darwin's views and those of modern geneticists. To Darwin, he said, variation in living forms is caused by external factors, crossing, or "undetermined" changes of internal origin. Since in his time there were no experimental data to study the internal causes of

variation, Darwin, according to Regel', was compelled to leave this problem for future generations. At long last, the advances in genetics during the first decade of the twentieth century made this possible. These advances, he thought, marked a full collapse of the Lamarckian environmental bias built into Darwin's theory, and a triumph for Mendel's mathematical approach to the study of hybridization. They produced extensive improvements in the physicochemical analysis of organic processes, and a confirmation of natural selection as a mechanism of organic evolution. As he saw them, mutations appear only in individual organisms. His contention that the "individual" origin of mutations and the cumulative effects of natural selection are the keys to an understanding of the transformation of living forms placed him among the early ancestors of the idea of synthetic evolution.^[78]

At the end of the first decade of the twentieth century, the new theories showed clear signs of taking root in Russian science. In 1910 Mendel's classic was translated into Russian, and its ideas began to spill into the larger community. A year later N. I. Vavilov presented a paper at the Golitsyn's Women's Courses in Agriculture, reviewing the salient points of Mendel's laws of heredity, Korzhinskii's and de Vries's "mutationism," and Johannsen's theory of "pure lines." In his opinion, the rise of genetics in Russia was closely related to the rapid growth of selection stations in southern and eastern regions and to the emergence of breeders as a professional group.^[79]

In 1912 a group of scientists began to publish Nature (Priroda ), a monthly journal devoted to making the knowledge of current developments in science accessible both to specialists and to the educated public. The journal placed particularly strong emphasis on current developments in genetics. It published popular and relatively favorable reviews of Russian translations of Western books dealing with the mechanism of heredity and its relation to organic evolution.^[80] A group of enterprising young biologists published a series of books, entitled Bios, which featured studies in experimental biology, especially genetics. In 1913 a leading theological journal published a detailed article on Mendelian genetics, greeting it as a step toward a full reconciliation of religion and modern science—and as a major defeat for Darwinism.^[81] In the same year Iu. A. Filipchenko, a budding geneticist, was appointed instructor at St. Petersburg University with the assignment of offering an introductory course in modern genetic theory.^[82] While universities continued generally to be the strongholds of Darwinism, the new institutions of

higher technical education and new specialized research centers, less bound by tradition and vested academic interests, were much more hospitable to the new theories.

In 1914 the British Journal of Genetics published a paper on the genetic basis for the immunity of certain cereals to fungous diseases, written by Nikolai Vavilov, a young Russian geneticist. The paper considered the physiological study of fungal reactions as a source of information on the genetic relations of plant forms.^[83] It clearly indicated that the Russian scientific community was ready to make original contributions to genetics. The Proceedings of the Bureau of Applied Botany added a new dimension to its deep commitment to the advancement of the new science of variation and heredity: it began to wage an open war on the more belligerent enemies of genetics.^[84]

E. A. Bogdanov, professor of animal husbandry at the Moscow Agricultural Institute, digressed from the main line of his scholarly interest in 1914 to produce a thick volume on Mendel's theory—on its scientific content and practical applicability. Loosely organized and unwieldy, the tome did not attract the attention it deserved. A broad and astute defense of Mendel's contributions to modern science was its most distinctive feature. "Mendel's notion of evolution," Bogdanov wrote, "relies primarily on fact, observation, and experiment, and on the elimination of errors and careful verification of conclusions." Bogdanov barely touched on the interrelation of Mendelism and Darwinism. He criticized "orthodox Darwinists" for their unwillingness to recognize important points of contact between the two theories. While recognizing the universal role of selection in the evolutionary process, he stuck to Mendel's views that denied random variation as a source of new species. Bogdanov did not use Mendel's theory as an anti-Darwinian weapon; what he wanted was a recognition of genetics as a key link in the realm of Darwinian thought. Obviously referring to Timiriazev, he lamented the strong role of authority in Russian biology, which stood in the way of critical thought, the cognitive fountain of science. To dramatize his point, he linked orthodox Darwinists to D. I. Pisarev, "the idol of the youth" and the culture hero of the nihilist intelligentsia in the 1860s, who relied on the authority of Ludwig Büchner in dismissing Pasteur's bacteriological theory as a legitimate part of science.^[85]

Without mentioning his name, Bogdanov criticized Timiriazev, the living link with the Pisarev era, for his unfair and abusive treatment of Mendel. He referred scornfully to Timiriazev's assertion that Darwin clearly anticipated the basic points of Mendel's theory, and that Men-

delian genetics was a unique expression of "pan-Germanic aspirations" and a weapon of clericalism.^[86] If genetics was a German conspiracy, why, he asked, did it develop most intensively in the United States and Great Britain? He hinted that, in his blind devotion to Darwinian orthodoxy, Timiriazev displayed a kind of hero worship that was most injurious to science. His defense of Mendel, however, did not prevent Bogdanov from expressing genuine admiration for the greatness of Darwin's achievement.

Small in number and weak in influence, the geneticists worked on two fronts: they took on the challenging task of advancing and popularizing the new theories, and they used every opportunity to stress their affinity with the Darwinian tradition. Even when individual geneticists reduced natural selection to a secondary position in the evolutionary theory, they did not challenge the gigantic proportions of Darwin's contributions to the great triumphs of modern science. Darwin, after all, made biology an empirical science, and, as Hermann Helmholtz had pointed out, he replaced metaphysical teleology by naturally evolved purposiveness—he chased the ghosts out of the realm of biology.

In their views on the factors of evolution, Russian geneticists were now clearly divided into two groups: the group attaching primary significance to natural selection, and the group placing the central emphasis on mutations and Mendelian laws of heredity.

N. K. Kol'tsov was the most dynamic and most articulate spokesman for the first group. His lavish praise of Darwin's contributions to evolutionary biology was part of a strategy to appease K. A. Timiriazev, a powerful member of the scientific community and a bitter foe of serious tampering with Darwinian thought. True to his appeasement strategy, he wrote:

Among Russian naturalists, the name of K. A. Timiriazev has been profoundly respected for a long time. More than one generation has learned biology from his books, and his numerous students and admirers have seen in him one of the pioneers of Russian Darwinism, who has contributed more than any other person to the advancement of the evolutionary idea. . . . Naturally, the merciless criticism of Mendelism coming from such a high authority has made various segments of Russian society suspicious of the new theory: many persons now view Mendel's and de Vries's theories as anti-Darwinian orientations. In his published papers and public speeches, this writer has fought for a long time against such a position.^[87]

Despite the most favorable attitude toward Darwin and Darwinian tradition, Kol'tsov never abandoned the idea that genetics stood an ex-

cellent chance of adding new substance and new theoretical insights to the very core of evolutionary thought. While paying homage to Darwin and his contributions to modern biology, he chose the powerful challenges of genetics for the central concern of his professional involvement in science. Not only did he not turn against the "physicochemical analysis" as a sure scientific path to the secrets of life, but, on the contrary, he became an internationally recognized pioneer in laboratory work that led many years later to the discovery of the macromolecule of heredity and to the triumph of molecular biology.

Kol'tsov made no secret of his profound dedication to the cause of modern genetics and experimental biology in general. This dedication did not stop him from placing natural selection, which he identified as "Darwin's law," on the same plane with Newton's law of gravitation.^[88] Just as Newton's law made it unnecessary to rely on miracles in interpreting the order of the physical universe, so "Darwin's law" took the whim of miracles out of living nature. "Darwin's law," however, did not reduce the importance of Mendel's and de Vries's theories for an understanding of organic evolution: these theories opened the previously inaccessible mysteries of living nature to scientific analysis and harnessed the tools of experimental study in support of evolutionary theory. Kol'tsov viewed evolutionary theory as both a world outlook and a scientific axiom. Darwin's major contribution, he thought, was in bringing about the triumph of evolutionary theory as a world outlook; the major contribution of Mendel and de Vries was in giving firmer footing to the scientific theory of evolution.^[89]

Iu. A. Filipchenko was the most eloquent and the most advanced representative of the other extreme in the views of Russian geneticists on the place of Darwin in modern evolutionary biology: he thought that natural selection was not the primary wheel of the evolutionary process. He was firmly convinced that the study of the mechanism of heredity held the primary key to the understanding of organic evolution (which was not true in Darwin's case) and that the basic answers must be sought outside the framework of Darwinian theory. He contended that the causes of variation—the building blocks of evolution—are inside organisms rather than in the outside environment; he was an unswerving advocate of autogenesis.^[90] Nor was "simple [nonmutational] variation," which Darwin had in mind, the real cause of evolution, for it was not hereditary. Relying on the experiments of Mendel, de Vries, and Johannsen, Filipchenko concluded that neither natural selection nor "slight modification" was a prime mechanism of the transformation of species.

He admitted, however, that all this was not sufficient ground for turning against Darwin; it merely meant a shift of emphasis to the more general aspects of Darwin's contributions. The more the idea of natural selection and "slight modification" retreated to a secondary plane of evolution, the more biologists were inclined to give Darwin credit primarily for transforming biology into an inductive science, for recognizing natural causality as the exclusive mechanism of scientific explanation in the life sciences, and for establishing evolution as the supreme integrative principle of biological knowledge.

Filipchenko represented the biologists who contended that "natural selection," "the struggle for existence," the stochastic nature of variation, and the continuity of change were not Darwin's major claims to fame in the first place. Darwin's major contribution, as he saw it, was in making evolution an unchallengeable fact of science and in elevating biology to the level of a true natural science. Even some of the most ardent Darwinists now admitted that the theory of natural selection did not preclude the possibility of alternative or parallel theories of biological evolution. Darwin's theory produced an indisputable result: it brought forth the "permanent and irrevocable" downfall of the idea of the static nature of living forms.^[91]

In Heredity, published in 1917, Filipchenko consolidated his firm allegiance to modern genetics based on autogenesis and Mendelian laws of heredity. This did not deter him from paying homage to Darwin as the main contributor to the rise of evolutionism in biology. Changing his strategy somewhat, now he selected two of Darwin's principles for particular emphasis: variation as a source of organic evolution, and heredity as the mechanism of generational transmission of variations. Filipchenko pointed to the Origin of Species as a pioneering study of the sources of variation and to The Variation of Animals and Plants Under Domestication as a detailed explication of pangenesis, the mechanism of heredity. This did not mean that he accepted Darwin's interpretation of variation and heredity: it meant, however, that he was ready to concede that the interpretation of these principles by modern experimental biology was not a negation but an elaboration and a refinement of Darwin's scientific ideas. While admitting that de Vries's "intracellular pangenesis" is far from a simple recasting of Darwin's theory, he was eager to point out a genetic similarity of the two views. Filipchenko reminded his readers that the paniculate carriers of heredity, variously named by contemporary biology, were descendants of Darwin's gemmules.^[92] He accepted all the digressions of modern genetics from Dar-

win's postulates, but he also worked hard not to be labeled an anti-Darwinist.

In 1917 Filipchenko noted that the study of variation and heredity, the subject matter of genetics, had made more progress during the past ten years than during the previous one hundred years. Impatient with biologists who ignored the pressing need for integrating the knowledge of genetics into the general theory of evolution, he criticized Les théories de l'évolution by Y. Delage and M. Goldsmith, which appeared in a Russian translation in 1916, for its failure to relate the developments in genetics to the theory of evolution. He considered the book an "anachronism."^[93] Nor did he see how a modern discussion of natural selection could overlook Johannsen's experimental study of "pure lines," or how a modern biologist could consider Weismann's "anachronistic" studies the most substantial contribution to the theory of heredity.^[94] The function of genetics, according to Filipchenko, was not to "liquidate" the theory of evolution but to build it on firmer foundations. In 1916 and 1917 Priroda carried his annual bibliographical analysis of major developments in various branches of genetics.^[95]

The sparse ranks of Russian geneticists received wholesome and beneficial encouragement from isolated scientists working in other fields of biology. The most noted among these scientists was D. I. Ivanovskii, the discoverer of the virus of tobacco mosaic. In 1908 he delivered the annual "university lecture" in Warsaw, where he taught microbiology and plant physiology. The annual "university lectures" were festive occasions at all Russian universities and honored the outstanding members of the academic community. In his address, Ivanovskii argued that the experimental method is indispensable to the study of organic evolution, but that it alone cannot answer all the questions. The future of evolutionary biology, he said, is in a combination of Darwin's legacy and recent products of experimental research. He thought that experimental biology rested on three principles: a reaffirmation of the paramount evolutionary role of the external environment (he obviously had in mind a branch of Lamarckian experimental biology); a recognition of the primacy of mutations in the origin of species; and a full acceptance of natural selection as the chief mechanism of organic transformation. In drawing his conclusions, Ivanovskii was strongly inclined to view the new biology as a combination of Lamarckian environmentalism, de Vries's mutationism, and Darwin's theory of natural selection. For unspecified reasons, he made no mention of revived and reinvigorated Mendelism. He noted that de Vries's mutation theory was a product of refined observation techniques rather than of the experimental method.^[96]

Ivanovskii admitted that the future development of evolutionary research would be inseparable from advances in experimental biology. He noted, however, that the new evolutionary theory was still too fluid to be conducive to successful empirical testing. This interpretation did not prevent him from concluding that the time for a general reevaluation of the factors of organic evolution was approaching fast. He thought that this reevaluation would result in downgrading natural selection as a "negative factor" and in upgrading variation and heredity as "positive factors."^[97]

The New State of Darwinian Biology:
A General Picture

In the West, more than in Russia, the architects of the new orientations in experimental biology gave prominence to strongly stated anti-Darwinian views, creating the impression of a rapidly approaching collapse of Darwin's theory. The threat to Darwinism, however, appeared much stronger than it actually was. The anti-Darwinian camp lacked unity and consolidation. Bateson, for example, was very reluctant to tie Mendel's laws of heredity to the burgeoning chromosome theory, a challenging and most promising development at the time. He represented those geneticists who "tended to see the particulate theory of inheritance as bordering on preformation."^[98] In general, the conflict between Pearsonian biometricians and Mendelians was bitter and intense. As a result of his experiments with the fruit fly Drosophila melanogaster in 1910, Thomas H. Morgan accepted Mendelism but also became convinced that many mutations were neither "jumps" nor parts of heritable characteristics.^[99] In a modified form, he went back a distance toward Darwin's "slight modification" and the law of natural selection. The Dutch biologist I. P. Lotsy attracted considerable attention with an original theory that recognized the gene theory while rejecting mutationism. While some geneticists fought against the "materialistic" bias of the chromosome theory, others thought that the main strength of the new genetics was in its unveiling of the secrets of the corpuscular basis of heredity, the main stumbling block to understanding organic evolution.

No new development was strong and comprehensive enough to replace Darwinism as a general evolutionary view of life. Mendelism was generally thought of as a brilliant development that strengthened the scientific study of heredity while leaving the other aspects of transmutation generally unattended. The mutation theory faced similar criticism. It was widely thought that, at best, mutations could be regarded only as

one source of evolutionary change. Neo-Lamarckism was diffuse and far removed from the most promising and rigorous domains of experimental research. Various neovitalist schools were too preoccupied with building metaphysical enclaves to give serious attention to questions of a methodological nature.

In 1907 V. L. Kellogg offered a pertinent summary of the situation on the biological front:

The basic truth is that the Darwinian selection theories, considered with regard to their claimed capacity to be independently sufficient mechanical explanations of descent, stand today seriously discredited in the biological world. On the other hand, it is also fair to say that no replacing hypothesis or theory of species-forming has been offered by the opponents of selection which has met with any general or even considerable acceptance by naturalists. Mutations seem to be too few and far between; for orthogenesis we can discover no saltatory mechanism; and the same is true for Lamarckian theories of modification by cumulation, through inheritance of acquired or ontogenetic characters.^[100]

There was also another development that worked in favor of the Darwinian positions: the pronounced inclination of the scientific community to look at most new advances in biology as realizations of fertile ideas Darwin had presented in his numerous published works. Darwin's theory of pangenesis, for example, was now interpreted as an ancestor of the involvement of modern genetics in the nuclear basis of heredity. Individual commentators noted that Darwin did not exclude saltatory evolution as one of several possible modes of change in living forms.

The anti-Darwinism of the new genetics peaked quickly and began to show signs of receding. In 1909 de Vries and Bateson were among those who gathered at Cambridge University to commemorate the onehundredth anniversary of Darwin's birth, to celebrate the fiftieth anniversary of the publication of the Origin of Species, and to reaffirm their respect for the scientific legacy of the English naturalist. These and most other leaders of the new science were eager and ready to note that modern transformism owed a primary debt to Darwin and that the future of biology belonged to a synthesis of diverse theoretical ideas among which Darwin's contributions occupied a preeminent position. De Vries, widely heralded as the most powerful enemy of Darwin's theory, said that whether variations arise from "simple fluctuations," as Darwin thought, or from mutations, as he believed, natural selection "will multiply them if they are beneficial, and in the course of time accumulate them," producing a great diversity of organic forms. Darwin may have been only

partially correct when he identified minute digression as the real stuff of evolution; but he was absolutely correct in making natural selection the real factor determining the course of evolution.^[101]

Darwin helped prepare the way for modern biological advances not only by suggesting topics for future research, but also by deliberately making the basic principles of his general theory open-ended and amenable to exceptions. Bateson found it appropriate to remind his Cambridge listeners that Darwin never abandoned his early conviction that "natural selection has been the main but not the exclusive means of modification."^[102]

Soon the representatives of Darwinian and Mendelian biology were united in recognizing natural selection as a mechanism of evolution. To be sure, there were differences: whereas to the Darwinists natural selection was a primary mechanism, to the Mendelian scholars it was a secondary mechanism. Nevertheless, individual biologists hinted at the possibility of unifying Darwinian and post-Darwinian biology. The theory of evolutionary synthesis, however, did not triumph until the late 1920s and the early 1930s. The emergence of population genetics in the mid-1920s gave biology inner order and theoretical consistency, without which no evolutionary synthesis could be profitably undertaken.

The upsurge in biological thought gave new direction to evolutionary research. It achieved this by improving experimental techniques, by advancing more effective procedures of field investigation, by adopting theoretical models from the rapidly advancing post-Newtonian physics, and by soliciting help from such previously detached sciences as mathematics and psychology. The excellence of the new evolutionary research was not in producing new ideas but in giving a sense of urgency and concreteness to a number of general notions that coexisted with—and were in opposition to—Darwin's theory. In one form or another, the idea of "sudden jumps" in the evolutionary process had been part of standard criticism of Darwin's theory since the early 1860s, when Kölliker introduced the notion of heterogenesis. The idea of the independence of heredity factors from the environment received strong support from Bateson's research almost a decade before the rediscovery of Mendel's laws. Somewhat earlier it became a key part of Weismann's elaborate logical constructions related to the cytological basis of heredity. The much-heralded orthogenesis of Eimer and Cope stood in direct opposition to Darwin's idea of the random nature of variation. The pressure for a systematic study of the psychological dimension of evolution came from many sides, panicularly after Wundt's bold effons to tie ex-

perimental psychology to the evolutionary idea. Romanes's work on physiological evolution had an appreciative and growing audience, as did the new vitalistic metaphysics (Henri Bergson) and vitalistic biology (Hans Driesch).

The appearance of the mutation theory and the rediscovery of Mendel's heredity laws did not precipitate immediate and extensive retooling of biological research. The process of translating the new theories into research strategies was rather slow. It was not until the end of the decade that the designs for new research acquired tolerable precision and that carefully conceived and organized inquiries were in full swing. The work of Thomas G. Morgan in the United States, William Bateson in Great Britain, and W. Johannsen in Denmark, and the founding of the first two journals in genetics—the Zeitschrift für Vererbungslehre (1908) in Germany and the Journal of Genetics (1910) in Great Britain—played a major part in helping the new research to acquire a solid foothold in the scientific community.

As it developed in Russia, the new world of biology had four distinguishing national characteristics. First, the new biology did not receive much help from the most distinguished national scientific centers—from the St. Petersburg Academy of Sciences and from St. Petersburg and Moscow universities. Its main support came from the new institutions, still involved in rapid growth and unencumbered by rigidly defined curricula or by vested academic interests. Indeed, the leading universities continued to be the bastions of Darwinism, pure or tempered. Second, it was the botanists, rather than the zoologists, who produced the chief architects, defenders, and articulators of developments in biology that went against the cardinal principles of Darwin's theory. The fact that an overwhelming majority of Western geneticists came from a botanical background had much to do with this phenomenon. Third, a majority of Russian scientists actively engaged in genetic research belonged to the younger generation of scholars. Employment insecurity and a low standing in the hierarchy of academic ranks influenced them to exercise restraint in their criticism of Darwinism, fervently defended by the luminaries of the older generation. Fourth, the Russian biologists avoided extremist philosophical positions. They favored a middle-of-the-road synthesis of opposing orientations. A typical biologist was willing to listen to neovitalist arguments only as a critique of the more extreme claims of mechanical philosophy. More than ever before, philosophical discourse occupied a strategic position in the critical examination of new developments in the leading branches of biology. This discourse,

however, displayed neither particular depth nor a propensity for dogmatic system-building.

The triumph of genetics, the unmistakable sign of the new age, compelled the Darwinian scholars to give serious thought to recasting the ideas of random variation, heredity, and natural selection as an adaptation to new advances in biology. It made geneticists determined not to discard Darwin's legacy but to make it part of the general onrush of modern scientific currents. Geneticists gained strength on both philosophical and practical fronts. On the philosophical front, they benefited from mounting challenges to the reigning ideas of the mechanistic orientation in science—challenges that came from both ontological and epistemological criticism. On the practical front, they had succeeded in alerting the rapidly growing ranks of scientific breeders to the enormous potential of the new techniques of crossing domestic varieties and species.

Although the rise of experimental biology challenged some of the cardinal principles of Darwin's theory, it did not seriously affect the preeminent position of Darwinian thought within the general context of evolutionary biology. M. V. Arnoi'di, professor of botany at Kharkov University, gave what may be considered the most typical assessment of the current state of Darwin's contributions. He wrote in 1904 that all new theories actually concentrated on expanding and clarifying Darwin's ideas. He was not surprised when de Vries identified himself as Darwin's follower. In his view, every effort to explain organic evolution "must begin with Darwin."^[103]

A new encyclopedia referred to Darwin as "the Copernicus or Newton of the organic world." It noted that by proclaiming man a member of the animal world, Darwin brought "the sciences of man" into close contact with the natural sciences and made the "genetic method" the main research tool of many fields of scientific inquiry.^[104] By categorizing man as an animal, he vastly expanded the scientific study of human society and culture. Expressing an unduly optimistic view, the anonymous writer noted that the enemies of Darwin's ideas had been silenced long ago. Published in 1902, the article appeared before the challenge of genetics had begun to take on the proportions of an avalanche. Another article in the same encyclopedia noted that the rejection of individual propositions of Darwin's theory should in no way be construed as a rejection of the theory as a whole.^[105] The author had no reservations about viewing Darwinism as an "indestructible" scientific theory.