This paper aims to provide a fresh historical perspective on the debates on vitalism and holism in Germany by analyzing the work of the zoologist Hans Spemann (1869–1941) in the interwar period. Following up previous historical studies, it takes the controversial question about Spemann’s affinity to vitalistic approaches as a starting point. The focus is on Spemann’s holistic research style, and on the shifting meanings of Spemann’s concept of an organizer. It is argued that the organizer concept unfolded multiple layers (...) of meanings (biological, philosophical, and popular) during the 1920s and early 1930s. A detailed analysis of the metaphorical dynamics in Spemann’s writings sheds light on the subtle vitalistic connotations of his experimental work. How Spemann’s work was received by contemporary scientists and philosophers is analyzed briefly, and Spemann’s holism is explored in the broader historical context of the various issues about reductionism and holism and related methodological questions that were so prominently discussed not only in Germany in the 1920s. (shrink)

This article explores the collaborative research of the Nobel laureate Hans Spemann (1869–1941) and the Swiss zoologist Fritz Baltzer (1884–1974) on problems at the intersection of development and heredity and raises more general questions concerning science and politics in Germany in the interwar period. It argues that Spemann and Baltzer’s collaborative work made a significant contribution to the then ongoing debates about the relation between developmental physiology and hereditary studies, although Spemann distanced himself from _Drosophila_ genetics because of his anti-reductionist (...) position. The article analyzes how Spemann framed the issues of heredity in terms of an epigenetic principle in the context of his work on the “organizer,” and it explores the experimental dynamics of research on newt merogones carried out by Baltzer in a methodological development of Spemann’s constriction experiments. Finally, these research attempts are discussed as part of a broader “prehistory” of the mid-twentieth century cell nuclear transplantation experiments, which provided the basis for later animal cloning. (shrink)

Hans Spemann's use of the concept double assurance, drawn from engineering models in cytology, is discussed in his work on lens development and the action of the organizer. His transformation of this concept within his neo-Lamarckian program is demonstrated and connected with the cultural factors which shaped engineering and embryology in Weimar Germany.