This article is about the beginnings of tissue culture-the culture of living, reproducing cells of complex organisms outside the body. It argues that Ross Harrison's experiments in nerve culture between 1907 and 1910 should be viewed as part of a larger shift in early twentieth-century laboratory practice from in vivo to in vitro experimentation. Via a focus on the temporality of experiment-contrasting the live object of Harrison's investigation with the static object of histological representations-this article details the production of a (...) new and surprising form of life, cellular life in vitro. Tissue culture, developed from Harrison's experiments, was greeted with great surprise and disbelief, despite Harrison's protestations that he had merely juxtaposed extant techniques. An analysis of these initial reactions to tissue culture illuminates the extent to which cells living visibly outside of the body in glass broke with in vivo practices and assumptions of the hiddenness and interiority of certain processes of growth and change. (shrink)

Stem cells did not become a proper research object until the 1960 s. Yet the term and the basic mind-set—namely the conception of single undifferentiated cells, be they embryonic or adult, as the basic units responsible for a directed process of development, differentiation and increasing specialisation—were already in place at the end of the nineteenth century and then transmitted on a non-linear path in the form of tropes and diagrams. Ernst Haeckel and August Weismann played a special role in this (...) story. The first coined the term Stammzelle (stem cell), the second was the author of the first cellular stem-tree diagram. Even today, I shall argue, the understanding of stem cells, especially the popular perception, is to a large extent a Haeckelian–Weismannian one. After having demonstrated this, by analysing the terminology, in this essay I will focus on the use of cytogenetic tree diagrams between 1892 and 1925 and on the tacit understanding of stem cells that they transmit. (shrink)

While historians of the microscope currently consider that no programme of microscopy took place during the Enlightenment, the thesis challenges this view and aims at showing when and where microscopes were used as research tools. The focus of the inquiry is the research on microscopic animalcules and the relationship of European microscope making and practices of microscopy with topical trends of the industrial revolution, such as quantification. Three waves of research are characterised for the research on animalcules in the Enlightenment: (...) 1. seventeenth-century observations on animalcules crowned by Louis Joblot's 1718 works in the milieu of Paris Académie royale des sciences, 2. mid eighteenth-century observations and experiments on polyps and animalcules (Trembley, Baker and Hill) and, 3. between 1760 and 1790, OF Müller's establishment of the systematics of infusoria in Denmark and Germany. (shrink)