Wilhelm His and mechanistic approaches to development at the time of Entwicklungsmechanik

Abstract

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 (1850-1924), 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' (1831-1904) 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.

Bioelectric signaling as a unique regulator of development and regeneration

“…In particular, an overlay of bioelectric signaling analyses onto a framework of developmental processes and concepts, such as induction, competence, capacitance and morphogenic fields, may provide important insights into the unique role bioelectric signaling plays in organizing life, while still retaining hypotheses that are addressable in reductionist analyses. Thus, once broken down to the component levels of analysiscell, compartment, tissue, organ/structure and organismthe study of bioelectric signaling can be embraced by the notion of developmental mechanics, or 'Entwicklungsmechanick', as an empirical approach (Dupont, 2017;Maienschein, 1991). The emergent properties imparted via bioelectric signaling, which allow it to coordinate functions within cells and tissues and across structures, may represent a fundamentally unique property of development that stands apart from, and integrates, canonical signaling networks.…”

The revolutionary developmental biology ofWilhelmHis,Sr.

“…In recent years, several historians and biologists have discussed His's research (e.g. Gould, 1977;Maienschein, 1991;Nyhart, 1995;Hopwood, 1999Hopwood, , 2000Hopwood, , 2002Hopwood, , 2005Hopwood, , 2007Hopwood, , 2012Hopwood, , 2013Richardson & Keuck, 2001;Hoßfeld & Olsson, 2003;Brauckmann, 2006;Laubichler, Aird & Maienschein, 2007;Richards, 2008;Dupont, 2017;Glover et al, 2018). His is well-known for his 'mechanical' theories of development.…”

Inferring cell junction tension and pressure from cell geometry

“…The roles of mechanical interactions during morphogenesis, proposed more than one century ago (His, 1874;Thompson, 1917;Dupont, 2017), are now well recognized. Forces are generated by molecular motors, notably by actomyosin networks, and are transmitted via cytoskeletal elements through cell-cell adhesive complexes.…”