With Carl Gegenbaur and Ernst Haeckel, inspiredby Darwin and the cell theory, comparativeanatomy and embryology became established andflourished in Jena. This tradition wascontinued and developed further with new ideasand methods devised by some of Haeckelsstudents. This first period of innovative workin evolutionary morphology was followed byperiods of crisis and even a disintegration ofthe discipline in the early twentieth century.This stagnation was caused by a lack ofinterest among morphologists in Mendeliangenetics, and uncertainty about the mechanismsof evolution. Idealistic morphology was stillinfluental in (...) Germany, which prevented a fullappreciation of the importance of Darwinstheory of natural selection for comparativemorphology. Evolutionary morphology andembryology failed to contribute significantlyto the modern synthesis of evolutionarybiology, thereby probably delaying theintegration of developmental biology intomodern evolutionary biology. However, Haeckelsstudent Oscar Hertwig, as well as Victor Franzand Alexej N. Sewertzoff from a youngergeneration, all tried to forge their ownsynthetic approaches in which (inspired byHaeckels work) embryology played an importantrole. Important for all three researchers wereattempts to refine, and sometimes redefine, thebiogenetic law, and to find new scientificexplanations for it (and for the manyexceptions to it). Their research was latermore or less forgotten, and had littleinfluence on the architects of the modernsynthesis. As the relationship betweenevolutionary and developmental biology is nowagain rising in importance in the form ofEvo-Devo, we would like to draw attention tohow this earlier research tradition grappledwith similar questions to those now on theagenda, albeit from sometimes quite differentperspectives. (shrink)

Morphogenesis is one of the fundamental processes of developing life. Gastrulation, especially, marks a period of major translocations and bustling rearrangements of cells that give rise to the three germ layers. It was also one of the earliest fields in biology where cell movement and behaviour in living specimens were investigated. This article examines scientific attempts to understand gastrulation from the point of view of cells in motion. It argues that the study of morphogenesis in the twentieth century faced a (...) major dilemma, both epistemological and pictorial: representing form and understanding movement are mutually exclusive, as are understanding form and representing movement. The article follows various ways of modelling, imaging, and simulating gastrular processes, from the early twentieth century to present-day systems biology. The first section examines the tactile modelling of shape changes, the second cell cinematography, mainly the pioneering work of the German embryologists Friedrich Kopsch and Ernst Ludwig Gräper in the 1920s but also a series of classic, yet not widely known, studies of the 1960s. The third section deals with the changes that computer simulation and live-cell imaging introduced to the modelling of shape change and the study of cell movement at the turn of the twenty-first century. Although live-cell imaging promises to experiment upon and represent the living body simultaneously, I argue that the new visuals are an obstacle rather than a solution to the puzzle of understanding cell motion. (shrink)

For Uexküll, biology is the science of the organization of living beings. In the context of Entwicklungsmechanik, he refers to Driesch’s and Spemann’s experiments on the development of embryonic germ cells to prove that self-differentiating processes constitute organisms as natural objects. Uexküll focuses on the theory of such self-differentiating processes or organizations. The notion of organization implies for him a “technique of nature” that is capable of structuring organic and inorganic material according to plans and rules. These plans and rules (...) are part of the overall order of the world. As preformed sign systems or codes, they determine and regulate the development and existence of individual animal subjects in their specific Umwelten. (shrink)

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)

In biology the term “vitalism” is usually associated with Hans Driesch’s doctrine of the entelechy: entelechies were nonmaterial, bio-specific agents responsible for governing a few peculiar biological phenomena. Since vitalism defined as such violates metaphysical materialism, the received view refutes the doctrine of the entelechy as a metaphysical heresy. But in the early twentieth century, a different, non-metaphysical evaluation of vitalism was endorsed by some biologists and philosophers, which finally led to a logical refutation of the doctrine of the entelechy. (...) In this non-metaphysical evaluation, first, vitalism was not treated as a metaphysical heresy but a legitimate response to the inadequacy of mechanistic explanations in biology. Second, the refutation of vitalism was logically rather than metaphysically supported by contemporary biological knowledge. The entelechy was not a valid concept, because vitalists could neither formulate vital laws, nor offer convincing examples of experimental indeterminism. (shrink)

In the history of life sciences, it has often been argued that the individual organism emerged, around 1800, as a four-dimensional entity—a temporalized entity. Against this backdrop, the article asks how research on development contributed to structuring the time of the organism in terms of a historical process, that is, by understanding a given phenomenon as brought forth by what preceded it and as establishing conditions for what will follow, thus relating the past, the present and the future in a (...) specific way. To shed light on this conceptualization, we must take into account not only embryological research on morphogenesis but also physiological research on the genesis of vital functions and the causation of congenital anomalies. Three layers of structuring time in such research may be discerned: the making of a trans-natal continuity of the developing organism; a conceptualization of birth as a threshold of past and future that paradigmatically reveals the historical understanding of such developmental continuity; and an approach to intergenerational transmission that confronts developmental continuity with historical contingency. My contribution focuses on the work of William T. Preyer and Charles Féré but, in a genealogical vein, situates their work in the larger context of nineteenth-century research on development. (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)

At the end of the nineteenth century, approaches from experimental physiology made inroads into embryological research. A new generation of embryologists felt urged to study the mechanisms of organ formation. This new program, most prominently defended by Wilhelm Roux, was called Entwicklungsmechanik. Named variously as “causal embryology”, “physiological embryology” or “developmental mechanics”, it catalyzed the movement of embryology from a descriptive science to one exploring causal mechanisms. This article examines the specific scientific and epistemological meaning of the mechanistic approaches of (...) embryological development by focusing on Wilhelm His’ histogenetic work. Roux was neither the first, nor the only one to argue for an experimental exploration of causes in embryology. At the time of Roux, physiological explanations of the genesis of the anatomical forms were developing in parallel, not only in German-speaking countries, but in France, Switzerland and English-speaking countries as well. The experimental approach and the cellular descriptions of embryogenesis were already omni-present when Roux proposed his Entwicklungsmechanik. However, these approaches remained disjointed. It appears that it was Wilhelm His who first succeeded in combining the question of the causal factors determining epigenesis, which was closely connected with experimentation on, and cellular descriptions of, development, in a coherent and concrete synthesis, making him one of the true initiators of the developmental mechanics. (shrink)