What did it mean for something to be the “material basis” of life, or heredity, permeability, or metabolism before molecular biology? What conceptions of matter did biologists rely on as they tackled new research topics? In the latter half of the nineteenth century (and well into the twentieth) it was biological orthodoxy that protoplasm was the “material basis of life,” so much so that the protoplasm’s protean nature spawned what Robert Brain has called “protoplasmania”—an aesthetic, cultural, and scientific obsession with the so-called “living substance.” But life was not the only thing biologists in the nineteenth century studied, and in this paper I will show how other areas of biology even more particular “plasmanias” took hold, as other vital phenomena gained their own “plasms” in due course. The idioplasm, germ plasm, nucleoplasm, stereoplasm, endo- and ecto-plasms, even cytoplasm, became the calling cards for newly emerging (and contested) problem areas in cellular anatomy and physiology. In particular, I will argue that botanists, far more so than zoologists, insisted on tying hereditary and developmental phenomena to their material bases within the cell. From the beginning with Carl Nägeli’s idioplasm theory, botanical theories of “genetics” always made reference to the material reality of hereditary factors via physical chemistry—albeit a physical chemistry specific to plant physiology. By shifting the historiographical locus of cell theory and hereditary theory to the history of botany, I will show how hereditary theory encountered chemical theory, several generations before the revolution in molecular genetics.

In the course of their study of the heredity of flower color, William Bateson, Edith Rebecca Saunders and Reginald Punnett observed that in Sweet Peas and Stocks, the crossing of two white-flowered strains produced purple flowers. Bateson’s student Muriel Wheldale quickly recognized the potential of this observation for advancing “a chemical basis for Mendelian phenomena”. She assumed that by combining the Mendelian methods for determining the laws of pigment inheritance with chemical methods for the isolation and analysis of these pigments, it should be possible to elucidate the mode of action of Mendelian factors, and at the same time solve the problem as to what chemical processes underlie the production of anthocyanin pigments. In her view, chemists interested in explaining anthocyanin biosynthesis, and geneticists whose goal was to understand the operation of genes were in fact interested in one and the same mechanism. However, Wheldale didn’t make the breakthrough she had hoped for. It was her student Rose Scott-Moncrieff who, in collaboration with chemists Robert and Gertrude Robinson and geneticist William Lawrence, was able to establish in the 1930s that gene action is essentially a control of chemical processes. This second attempt was so successful, I will argue, because Scott-Moncrieff managed to convince the chemists and geneticists that joining forces with researchers from other disciplines would help them to solve their own research problems in an adequate way. Furthermore, I will use the case of anthocyanin research to highlight the significance of interfield objects and interfield practices in cross-disciplinary collaborations.

Much has been said about how the choice of experimental organisms matters, how they open possibilities and impose constraints on a research program and often push an inquiry in an unexpected direction. The same might be said about the kinds of phenomena researchers come to study as representative of a broader class of phenomena. Geneticists in the early twentieth century studied many characters to understand the patterns of heredity and their underlying cytological basis. Nonetheless, the color of flowers, seeds, or other parts of plants, as well as the color of fur and eyes in animals, were particularly prominent objects of study. Some researchers relied entirely on the phenomena of pigmentation in their projects; others worked with many characters but used the inheritance of color as a prime example in theoretical considerations. Most interestingly, the focus on pigmentation afforded possibilities for interfield transfer and collaboration between genetics and organic chemistry. In that way, it played an important role in shaping the conceptualization of gene action in early genetics. I will follow pigmentation as a research object in genetics from early Mendelian debates to the work of Beadle and Ephrussi in the US and France, and Kühn, Caspari, and Butenandt in Germany.

The collaborative marriage in 1920 between Sally Hughes and Franz Schrader emerged following their interaction at Woods Hole and the Zoology Department at Columbia University. Their personal and scientific interests matched perfectly, and they forged a fruitful scientific partnership that lasted over four decades. Both were avid naturalists before deciding to pursue graduate work in zoology. As students of E. B. Wilson, they became leading American cytologists (Franz indeed succeeded Wilson at Columbia in 1930). They were also influenced by interaction with T. H. Morgan and his group. Their long-term focus on chromosomes and their role in heredity, combined with avid field work to collect novel organisms, provides a model study by which to consider how “interfield” theories, methods, and approaches helped define the newly developing field of cytogenetics in the 1920s and 1930s. It also illuminates critical aspects of the reception of C. D. Darlington’s “new cytology” in the 1930s.

My paper will demonstrate how the character and the content of a discipline at a moment that it seems to have become a solid and accepted one, are still under vivid discussion. When the Fifth international meeting of geneticists in 1927 in Berlin took place, participants felt that genetics was now an established and accepted discipline. The organizer, the German Ernst Baur, stated that it had grown from an unimportant outpost to one of the most important biological disciplines. This importance was reflected in its relevance for eugenics and medicine and for the breeding of useful plants and animals. According to the British geneticist Reginald Punnett, genetics had gained a central position in biology thanks to its interdisciplinary character: it linked systematics, physiology, biochemistry, and Entwicklungsmechanik (developmental mechanics). Others argued, in turn, that its focus and techniques had become too narrow and that it needed to broaden its scope to be able to answer relevant questions. According to the Austrian Richard von Wettstein, genetics should step out of the narrow Mendelian framework to explain evolution and to include plasmatic inheritance and the inheritance of acquired characteristics. The German Richard Goldschmidt argued that not only the transmission of genetic factors but also their action through development had to be taken into account. Must the conclusion be that an established discipline can only remain strong when its adherents are conscious that its content and character are in a constant state of flux?