In 1889 Hugo de Vries published " Intracellular Pangenesis " in which he formulated his ideas on heredity. The high expectations of the impression these ideas would make did not come true and publication was negated or reviewed critically. From the reactions of his Dutch colleagues and the discussion with the famous German zoologist August Weismann we conclude that the assertion that each cell contains all hereditary material was controversial and even more the claim that characters are inherited independently of (...) each other. De Vries felt that he had to convince his colleagues of the validity of his theory by providing experimental evidence. He established an important research program which resulted in the rediscovery of Mendel's laws and the publication of "The Mutation Theory." This article also illustrates some phenomena that go beyond an interesting episode in the development of theories of heredity. It shows that criticism from colleagues can move a researcher so deeply that he feels compelled to set up an extensive research program. Moreover it illustrates that it is not unusual that a creative scientist is only partially willing to take criticism on his theories into account. Last but not least it demonstrates that common opinion on the validity of specific arguments may change in the course of time. (shrink)

Julian Huxley’s eclipse of Darwinism narrative has cast a long shadow over the historiography of evolutionary theory around the turn of the nineteenth century. It has done so by limiting who could be thought of as Darwinian. Peter Bowler used the eclipse to draw attention to previously understudied alternatives to Darwinism, but maintained the same flaw. In his research on the Non-Darwinian Revolution, he extended this problematic element even further back in time. This paper explores how late nineteenth-century neo-Darwinian conceptualizations (...) of Darwinism were later utilized by several advocates and detractors of the Modern Synthesis. John Beatty has shown how this continuity hinges at least partly on the perceived importance of the creativity of natural selection. The paper provides a more thorough look at Darwin’s two conflicting accounts of variation, ascribed to struggles in explaining quantitative versus qualitative characters. In doing so, it suggests that other forms of Darwinism persisted, in both the non-Darwinian revolution and eclipse periods, because of tension between contingency and creativity in Darwin’s own work. This tension is traced out from Darwin’s conceptions of variation into the work of Alfred Russel Wallace, Hugo de Vries, and Thomas Henry Huxley. Based on this, the eclipse narrative is criticized for not considering the meaning of Darwinism in different geographical locations. Britain and the United States showed few signs of an eclipse. Rather, the rise of German debates about Haeckel’s vision of Darwinism have been mistaken for a universal decline in support. (shrink)

According to a classical narrative, early geneticists, failing to see how Mendelism provides the missing pieces of Darwin’s theory, rejected gradual changes and advocated an implausible yet briefly popular view of evolution-by-mutation; after decades of delay (in which synthesis was prevented by personal conflicts, disciplinary rivalries, and anti-Darwinian animus), Darwinism emerged on a new Mendelian basis. Based on the works of four influential early geneticists – Bateson, de Vries, Morgan and Punnett –, and drawing on recent scholarship, we offer an (...) alternative that turns the classical view on its head. For early geneticists, embracing discrete inheritance and the mutation theory (for the origin of hereditary variation) did not entail rejection of selection, but rejection of Darwin’s non-Mendelian views of heredity and variation, his doctrine of natura non facit saltum, and his conception of “natural selection” as a creative force that shapes features out of masses of infinitesimal differences. We find no evidence of a delay in synthesizing mutation, rules of discrete inheritance, and selection in a Mendelian-Mutationist Synthesis. Instead, before 1918, early geneticists had conceptualized allelic selection, the Hardy–Weinberg equilibrium, the evolution of a quantitative trait under selection, the probability of fixation of a new mutation, and other key innovations. Contemporary evolutionary thinking seems closer to their more ecumenical view than to the restrictive mid-twentieth-century consensus known as the Modern Synthesis. (shrink)

Hugo de Vries (1848–1935) would without doubt turn in his grave if he could be told about the various perspectives from which historians have studied his ideas and works. His would not be an exceptional case, of course, for many before and after him have fallen victim to the irony of history. Still, I am inclined to grant de Vries that he would have some reason for his distress, for the irony has hit him particularly hard. In 1922, de Vries (...) was invited to attend the Mendel centennial celebrations at Brünn (Brno). He declined the invitation, suspecting, among other things, that the tenor of the commemoration would be pro-Mendel and anti-Darwin, and he heartily refused to share in either sentiment. Now contrast this with de Vries' imputed role in the historiography of genetics and evolutionary theory as ‘rediscoverer’ of Mendelism and as co-executor of the ‘eclipse of Darwinism’, and the irony will be clear. (shrink)

Recent studies have shown that Hugo de Vries did not rediscover Mendel's laws independently and that the classical story of the rediscovery of Mendel is largely a myth. Until now, however, no satisfactory account has been provided of the background and development of de Vries' views on heredity and evolution. The basic tenets of de Vries' Mutationstheorie and his conception of Mendelism are still insufficiently understood. It has been suggested that de Vries failed to assimilate Mendelism and that he wrote (...) his Mutationstheorie in a state of confusion. In this paper I argue that we can arrive at a better understanding by adopting a more symmetrical approach. My analysis will concentrate on three important aspects of de Vries' thinking which have been insufficiently appreciated until now. The first is that de Vries' reading of Mendel compelled him to change his conception of the hereditary particles, the pangenes, in a fundamental way. The second is de Vries' use of the notion of ‘hereditary force’. The third revolves around de Vries' typological species concept, which has been the source of much confusion in the literature. I shall conclude that de Vries did succeed in incorporating ‘Mendelism’ into his wider views on heredity and evolution, and that he did manage to handle his evidence in a consistent way. Yet I shall also conclude that Mendelism, in de Vries' interpretation, had nothing to do with ‘normal’ heredity and was mainly a laboratory phenomenon. (shrink)

This article discusses the contribution to evolutionary theory of Leonard Darwin, the eighth child of Charles Darwin. By analysing the correspondence Leonard Darwin maintained with Ronald Aylmer Fisher in conjunction with an assessment of his books and other written works between the 1910s and 1930s, this article argues for a more prominent role played by him than the previously recognised in the literature as an informal mentor of Fisher. The paper discusses Leonard’s efforts to amalgamate Mendelism with both Eugenics and (...) Darwinism in order for the first to base their policies on new scientific developments and to help the second in finding a target for natural selection. Without a formal qualification in biological sciences and as such mistrusted by some “formal” scientists, Leonard Darwin engaged with key themes of Darwinism such as mimicry, the role of mutations on speciation and the process of genetic variability, arriving at important conclusions concerning the usefulness of Mendelian genetics for his father’s theory. (shrink)

In June 1909, scientists and dignitaries from 167 different countries gathered in Cambridge to celebrate the hundredth anniversary of Charles Darwin’s birth and the fiftieth anniversary of the publication of Origin of Species. The event was one of the most magnificent commemorations in the annals of science. Delegates gathered within the cloisters of Cambridge University not only to honor the “hero” of evolution but also to reassess the underpinnings of Darwinism at a critical juncture. With the mechanism of natural selection (...) increasingly under attack, evolutionary theory was in disarray. Against this backdrop, biologists weighed the impact of several new developments—the rediscovery of Mendel’s laws of heredity, de Vriesian mutation theory, and the linkage of sex‐cell division to the mechanism of heredity. The 1909 Darwin celebration thus represents a significant watershed in the history of modern biology that allows historians to assess the status of evolution prior to the advent of the chromosome theory of genetics. (shrink)

This article considers the reception of British cytogeneticist C.D. Darlington's controversial 1932 book, Recent Advances in Cytology. Darlington's cytogenetic work, and the manner in which he made it relevant to evolutionary biology, marked an abrupt shift in the status and role of cytology in the life sciences. By focusing on Darlington's scientific method -- a stark departure from anti-theoretical, empirical reasoning to a theoretical and speculative approach based on deduction from genetic first principles -- the article characterises the relationships defining (...) the "disciplinary landscape" of the life sciences of the time, namely those between cytology, genetics, and evolutionary theory. (shrink)