¹ In writing this paper I have been much helped by discussions with Peter Bowler, Frederick Churchill, Lindley Darden, Jim Grisemer, Jon Harwood, Ernst Mayr, Robert Olby, Onno Meijer, Jan Sapp and Phillip Sloan.

² Mayr, E., The Growth of Biological Thought: Diversity, Evolution and Inheritance, Cambridge, Mass., 1982Google Scholar. A very recent paper greatly enhances our understanding of such issues: Carron, J. A., ‘“Biology’ in the Life Sciences, History of Science’, (1988), 26, pp. 223–268.Google Scholar

³ Bowler, P. J., Evolution: The History of an Idea, Berkeley and Los Angeles, 1984Google Scholar. But see also two sub sequent books by Bowler (notes 4 and 13).

⁴ For a sampling of these newer views of Darwin's programme, see Sloan, P. R., ‘Darwin's Invertebrate Program, 1826–1836: Preconditions for Transformism,’ in Kohn, D. (ed), The Darwinian Heritage, Princeton, 1985, pp. 71–120Google Scholar, and ‘Darwin, Vital Matter, and the Transformism of Species,’ Journal of the History of Biology, (1986), 19, pp. 369–445Google Scholar; Hodge, M. J. S., ‘Darwin and the Laws of the Animate Part of the Terrestrial System (1835–1837): On the Lyellian Origins of his Zoonomical Explanatory Program,’ Studies in the History of Biology, (1983), 6, pp. 1–106Google Scholar; ‘The Development of Darwin's general biological theorizing,’ in Bendali, D. S. (ed), Evolution from Molecules to Men, Cambridge, 1983, pp. 43–62Google Scholar, and ‘Darwin as a Lifelong Generation Theorist,’ in Kohn, D. (ed), The Darwinian Heritage, pp. 207–244Google Scholar. For a sampling of recent work on the history of theories of heredity and related topics, see Bowler, P. J., Mendelismi The Emergence of Hereditarian Concepts in Modern Science and Society, forthcomingGoogle Scholar; Churchill, F., ‘From Heredity Theory to Vererbung: The Transmission Problem, 1850–1915,’ Isis, (1987), 78, pp. 337–364CrossRefGoogle ScholarPubMed; Olby, R. C., Origins of Mendelism, 2nd edn., Chicago, 1985Google Scholar; ‘The Emergence of Genetics,’ in Olby, R. C., Cantor, G. N., Christie, J. R. and Hodge, M. J. S. (eds), Companion to the History of Science, forthcomingGoogle Scholar, and ‘Historiographical Problems in the History of Genetics,’ Rivista di Storia della Scienza, (1984), 1, pp. 25–38Google Scholar; Farley, J., Gametes and Spores: Ideas about Sexual Reproduction, 1750–1914, Baltimore, 1982Google Scholar. Extensive bibliographic guidance is also available in Brush, S. G., The History of Modern Science. A Guide to the Second Scientific Revolution, 1800–1950, Ames, Iowa, 1988.Google Scholar

⁵ Forbes, E. G. (ed), Human Implications of Scientific Advance: Proceedings of the XV International Congress of the History of Science, Edinburgh, 10–15 August 1977, Edinburgh, 1978Google Scholar. See Symposium No. 8.

⁶ The evidence of what is said in this and the next paragraph is set forth in the papers on Darwin, op. cit. (4).Google Scholar

⁷ The history of changing ideas and institutionalizations of physiology can be studied in Schiller, J., Physiology and Classification: Historical Relations, Paris, 1980Google Scholar; Lenoir, T., The Strategy of Life: Teleology and Mechanics in Nineteenth-Century German Biology, Dordrecht, 1982Google Scholar; Lesch, J., Science and Medicine in France: The Emergence of Experimental Physiology, 1790–1855, Cambridge, Mass., 1984CrossRefGoogle Scholar, and Pickstone, J. V., ‘Science in France,’ History of Science, (1988), 26, pp. 201–211CrossRefGoogle Scholar. See also Carron, op. cit. (2)Google Scholar. For correctives to common stereotypes of what natural history comprised in the 1830s, see Rehbock, P. F., The Philosophic Naturalists. Themes in Early Nineteenth-Century British Biology, Madison, 1983Google Scholar. The complexities in comparing physiological and morphological strategies of explanation are elucidated for one particular case in Churchill, F., ‘Hertwig, Weismann, and the Meaning of the Reduction Division Circa 1900,’ Isis, (1970), 61, pp. 429–458.CrossRefGoogle Scholar

⁸ The evidence for what is said in this and the next five paragraphs is set out in the papers on Darwin, op. cit. (4).Google Scholar

⁹ Wilson, E. B., The Cell in Development and inheritance, New York, 1900, pp. 1–13.Google Scholar

¹⁰ Churchill, F., ‘Sex and the Single Organism: Biological Theories of Sexuality in Mid-Nineteenth Century,’ Studies in History of Biology, (1979), 3, pp. 139–178.Google ScholarPubMed

¹¹ Weismann, A., Essays upon Heredity and Kindred Biological Problems, eds Poulton, E. B., Schönland, S. and Shipley, A. E., 2 vols, Oxford, 1891–1892Google Scholar; The Germ-plasm: A Theory of Heredity, trans. Parker, W. N. and Rönnfeldt, H., London, 1893Google Scholar. In addition to the papers of Churchill, op. cit. (4) and (7)Google Scholar, see his ‘August Weismann and a Break from Tradition,’ Journal of the History of Biology, (1968), 1, pp. 91–112Google Scholar; ‘Weismann's Continuity of the Germ-Plasm in Historical Perspective,’ Freiburger Universitätsblätter, (1985), 24, 107–124Google Scholar. I am grateful to Jon Harwood for making available to me a copy of the double issue of this journal devoted to Weismann under the title August Weismann (1834–1914) und die theoretische Biologie des 19. Jahrhunderts and edited by Klaus Sander. See, further, Churchill, , ‘Weismann, Hydromedusae and the Biogenetic Imperative: A Reconsideration,’ in Horder, T. J., Witkowsky, J. A. and Wylie, C. C., (eds), A History of Embryology, Cambridge, 1986, pp. 7–33Google Scholar; Baxter, A. and Farley, J., ‘Mendel and Meiosis,’ Journal of the History of Biology, (1979), 12, pp. 137–173CrossRefGoogle Scholar; Farley, , Gametes and Spores (op. cit. 4)Google Scholar; Mayr, E., ‘Weismann and Evolution,’ Journal of the History of Biology, (1985), 18, pp. 295–329CrossRefGoogle ScholarPubMed, also (in German) in the volume edited by Sander, K. and, as ‘On Weismann's Growth as an Evolutionist’, in Mayr, E., Toward a New Philosophy of Biology. Observations of an Evolutionist, Cambridge, Mass, 1988, pp. 491–524Google Scholar; Robinson, G., A Prelude to Genetics. Theories of a Material Substance of Heredity: Darwin to Weismann, Lawrence, Kansas, 1979Google Scholar. It is the indispensable achievement of Churchill and of Farley, in his invaluable book, to have given us the insights into nineteenth-century ideas about reproduction that historians of ‘evolutionary biology’ and of ‘genetics’ have long needed.

¹² On germinal selection see not only Weismann's essay, On Germinal Selection as a Source of Definite Variation, trs McCormack, T. J., 2nd edn, Chicago, 1902Google Scholar, but also his final, grand evolutionary synthesis: The Evolution Theory, trs , J. A. and Thomson, M. R., 2 vols, London, 1904Google Scholar, a synthesis Weismann continued to refine, not least in relation to Mendelism, up to the third German edition of 1910.

¹³ This distinction is put to use, especially, in Bowler, Mendelism (op. cit. 4)Google Scholar and The Non-Darwinian Revolution: Reinterpreting a Historical Myth, Baltimore, 1988Google Scholar. Meanwhile it is prominent in Sandler, I., and Sandler, L., ‘A Conceptual Ambiguity that Contributed to the Neglect of Mendel's Paper,’ History and Philosophy of the Life Sciences, (1985), 7, pp. 3–70Google ScholarPubMed, and Harwood, J., ‘Genetics and the Evolutionary Synthesis in Interwar Germany,’ Annals of Science, (1985), 42, pp. 279–301CrossRefGoogle ScholarPubMed, and ‘National Styles in Science: Genetics in Germany and the United States between the World Wars,’ Isis, (1987), 78, pp. 390–414.Google Scholar

¹⁴ Allen, G., ‘T. H. Morgan and the split between embryology and genetics, 1910–1935,’Google Scholar in Horder, et al. (eds) A History of Embryology, pp. 113–146Google Scholar. The relations between genetics and embryology in the decades around 1900 have been clarified importantly in several papers by J. Maienschein. See, especially, her ‘Preformation or new formation—or neither or both’ in the volume edited by Horder, et al. pp. 73–108Google Scholar, and ‘Heredity/Development in the United States circa 1900,’ History and Philosophy of the Life Sciences, (1987), 9, pp. 79–93.Google Scholar

¹⁵ The precise teaching of Weismann and his successors on the place in growth of the germ tracks and the soma is greatly illuminated in Grisemer, J. R. and Wimsatt, W. C., ‘Picturing Weismannism: A Case Study of Conceptual Evolution,’Google Scholar forthcoming in a volume edited by Ruse, M. and provisionally entitled What Philosophy of Biology Is.Google Scholar

¹⁶ On this subject generally (including Weismann on ontogeny and phylogeny), see Gould, S. J., Ontogeny and Phylogeny, Cambridge, Mass., 1977Google Scholar, and, for Chambers and Carpenter and their contemporaries, see Ospovat, D., ‘The Influence of Karl Ernst von Baer's Embryology, 1828–1859; A Reappraisal in Light of Richard Owen's and William B. Carpenter's Paleontological Application of “Von Baer's Law”,’ Journal of the History of Biology, (1976), 9, 1–28.Google Scholar

¹⁷ See the books of Bowler cited in n.13. I am preparing a review of Bowler's book for this journal.

¹⁸ The significance of Galton's thinking in this regard has been stressed by Olby, , Origins of Mendelism, pp. 55–64Google Scholar, following the analyses of Ruth Cowan. See, especially, her ‘Francis Galton's Contributions to Genetics,’ Journal of the History of Biology, (1972), 5, pp. 389–412.Google Scholar

¹⁹ See, especially, Olby, , Origins of Mendelism, pp. 196–258Google Scholar, and Callender, L. A., ‘Gregor Mendel: an Opponent of Descent with Modification,’ History of Science, (1988), 26, pp. 41–75.CrossRefGoogle Scholar

²⁰ Olby, , Origins of Mendelism.Google Scholar

²¹ For a contemporary version of this point, see Newman, H. H., Evolution, Genetics and Eugenics, revised edn, Chicago, 1925, p. 321Google Scholar: ‘though Mendel's laws appear to be merely laws of hybridization, they have a much wider application: they are really the laws of sexual reproduction.’ For Mendelism and sex determination, see Farley, , Gametes and SporesGoogle Scholar and Gilbert, S., ‘The Embryological Origins of the Gene Theory,’ Journal of the History of Biology, (1978), 11, pp. 307–351CrossRefGoogle ScholarPubMed. For the state of discussion before Mendelism see Geddes, P. and Thomson, J. A., The Evolution of Sex, revised edn, London, 1901.CrossRefGoogle Scholar

²² The three papers appeared, respectively, in The American Naturalist, (1922), 56, pp. 32–50Google Scholar; Proceedings of the International Congress of Plant Science, (1929), 1, pp. 897–921Google Scholar and The American Naturalist, (1931), 64, pp. 118–138Google Scholar. The first and parts of the other two are reprinted in Muller, H. J., Studies in Genetics, Bloomington, 1962Google Scholar. For Muller's thinking at this period the indispensable biography is Carlson, E. O., Genes, Radiation and Society: The Life and Work of H. J. Muller, Ithaca, 1981.Google Scholar

²³ On Troland and Muller's debts to him, see Olby, R. C., The Path to the Double Helix, London, 1974, pp. 112–113, 146–7 and 435–6.Google Scholar

²⁴ Ravin, A. W., ‘The Gene as Catalyst; the Gene as Organism,’ Studies in the History of Biology, (1977), 1, pp. 1–47.Google ScholarPubMed

²⁵ Muller, , ‘Some genetic aspects of sex,’ section 1Google Scholar, which is reprinted in Muller, , Studies, pp. 469–473Google Scholar. On these new views of mutation, see Olby, R. C., ‘La Théorie génétique de la selection naturelle vue par un historien’, in Colloque R. A. Fisher et l'Histoire de la Génétique des Populations in Revue de Synthèse, (1981), 103–4, pp. 251–290.Google Scholar

²⁶ Ravin, , ‘The Gene,’Google Scholar discusses Wright's debts to Troland. More generally, see Provine, W. B., Sewall Wright and Evolutionary Biology, Chicago, 1986Google Scholar. Wright went beyond the theory of life to a panpsychical theory of mind. His philosophical views, compared and contrasted with R. A. Fisher's, will be treated of in a paper now in preparation by John Turner and myself.

²⁷ For the many sources of Dobzhansky's synthesis, see, Mayr, E. and Provine, W. B., (eds), The Evolutionary Synthesis: Perspectives on the Unification of Biology, Cambridge, Mass., 1980CrossRefGoogle Scholar. His relations with Wright are covered in Provine, , Sewall WrightGoogle Scholar. The first edition of Genetics and the Origin of Species, New York, 1937Google Scholar, has been reprinted recently (1982) with an introduction by S. J. Gould, the publishers as before being Columbia University Press.

²⁸ It is telling that late nineteenth-century biologists often wrote on eighteenth-century generation theory, especially in connection with the revived issue of preformation and epigenesis.

²⁹ For example, it is instructive to see how Churchill's treatment of the Weismann-Spencer controversy over ‘soft’ heredity leads to the themes stressed here: ‘The Weismann-Spencer Controversy over the Inheritance of Aquired Characters,’ in Forbes, E. G. (ed), Human Implications of Scientific Advance. Proceedings of the XVth International Congress of the History of Science, Edinburgh 10–15 August 1977, Edinburgh, 1978, pp. 451–468Google Scholar. For a very full account of Lamarckian theorizing and other alternatives to the Darwinian selectionist tradition in this period, see Bowler, P. J., The Eclipse of Darwinism: Anti-Darwinian Evolution Theories in the Decades around 1900, Baltimore, 1983Google Scholar. Jan Sapp has been showing that a further contrast—nuclear versus cytoplasmic inheritance—can provide new insights into the intellectual and institutional history of genetics from 1900 on. See his paper ‘The Struggle for Authority in the Field of Heredity, 1900–1932: New Perspectives on the Rise of Genetics,’ Journal of the History of Biology, (1983), 16, pp. 311–342Google Scholar and his book, Beyond the Gene. Cytoplasmic Inheritance and the Struggle for Authority in Genetics, New York and Oxford, 1987.Google Scholar