International Society for History, Philosophy, and Social Studies of Biology


twitter 2015
     facebook 2015

Program

WEDNESDAY, JULY 8  /  11:00 - 12:30  /  DS-1545
Individual papers
On the Blood, Formato Foetu and Stem Cells

Walter Needham’s Disquisitio Anatomica de Formato Foetu

Ashley Inglehart (Indiana University Bloomington, United States)

This paper examines the historical significance and content of Walter Needham’s 1666 Disquisitio anatomica de formato foetu. Disquisitio, an impressive and rich embryological text, has been largely overlooked in the secondary literature. What little attention the treatise has received tends to focus on its resulting controversy with Danish anatomist, Nicolaus Steno. This treatise, however, is a significant contribution to embryology in its own right worthy of closer study. Inspired by the experiments conducted with Robert Boyle and other members of the so-called Oxford circle, Disquisitio focuses on the sanguification, respiration, and nutrition of the fetus in-egg or in utero. Because the mechanisms of both respiration and nutrition remained unclear and a subject of contention at the time of Needham’s investigations, his experiments on the fetus—itself a developing animal enveloped in amniotic fluid—are a rather ingenious attempt to understand more fully how these biological processes occur.


Descartes on the heart, blood, and Harvey

Jordan Taylor (University of Pennsylvania, United States)

The Cartesian human being is a conglomerate organism: a mixture of immaterial, volitional, sentient, and sapient mind-substance, on the one hand; and on the other, extension, manifesting itself as a complicated community of corpuscular particles--that is, material substance. This conception is an innovation on Descartes’s part, as it goes hand-in-hand with a novel physical account of the world that departs quite radically from the accepted class of theories of the seventeenth century. With a new understanding of the world’s principles and causes comes the burden of explaining the principles governing, and causes underlying, the world's inhabitants. Descartes therefore faces the difficult task of bringing the phenomena of the special sciences in line with the mechanistic corpuscular physics to which he subscribes. This paper focuses on Descartes’s theory of human physiology. More specifically, it traces his explanation of the circulatory system responsible for animating the human body. Descartes’s account of the motion of the blood is situated within a sophisticated reductionist framework that can account for complex behaviors and bodily functions by appealing, ultimately, to microscopic particles in motion. The paper also explores Descartes’s debt to Harvey and the ways in which Descartes’s theoretical commitments, as well as his practical outlook, forced him to contradict many of Harvey’s own vitalistic interpretations of his experimental observations.


Early conceptualisation of the embryonic stem cell

Cheryl Lancaster (Durham University, United Kingdom)

Stem cell history begins with theory, not physical entities. The phrase "stem cell" first appeared in print in 1868, in Ernst Haeckel's Natürliche Schöpfungsgeschichte. But what developments had been made in biology to allow Haeckel to reach this milestone? This presentation will consider several aspects of research in the context of late eighteenth and early nineteenth century European (and in particular German) universities, beginning with the identification of cells as the basic units of life, and Schwann and Schleiden's Cell Theory. In the early decades of the nineteenth century, a younger generation of naturalists took-up embryological study, and began by repeating those studies they had learned about as students. Four such researchers were Karl Ernst von Baer, John Evangelista Purkyně, Jean Louis Prévost, and Jean Baptiste Dumas. Purkyně chose chickens as his animal of study, identifying the germinal vesicle in chicken eggs; this was important work, bridging the gap between avian and mammalian embryology. von Baer’s work followed that of Dumas and Prévost, dissecting rabbits then a dog. Inside the dog, von Baer claims he observed an egg yolk, and published his observations in January 1828, describing the Graafian vesicle as the true mammalian egg. This egg provided a place for development, and became part of the foetus, possible due to the presence of the egg yolk. The presentation will also consider the practical aspect of embryology and development, from the seventeenth century work made possible due to the technological advances in optics, to the nineteenth century experiments carried out in attempts to prove or disprove various theories of the era. Such theories created debates over preformation, and whether the sperm or ova were the most influential germ in creation of new life. Eventually, this led to ideas regarding the egg as a cell – an important milestone in conceptualising embryonic stem cells. Foremost in this work was Carl Gegenbaur, a colleague of Ernst Haeckel. From the work describing the unfertilised egg as a cell, the natural conclusion to this was considering what occurred after fertilisation. Possibly the most informative work in this field was carried out in the late 1830s by Scottish physician Martin Barry. In a series of three reports to the Royal Society’s Philosophical Transactions, Barry described the maturation of the egg, and the first stages of development. This included identifying that the ‘vesicles’ that arise from division through early embryogenesis are ‘vesicles’ as described by others in the adult. This, I argue, is the first instance in embryology of any individual equating embryonic cells with adult cells. In the 1840s, Barry’s observations were confirmed by Carl Bergman (at the time, Wagner’s assistant at Göttingen), and Heinrich Rathke. This presentation will then consider how all of these developments led to Haeckel’s coining of the term Stammzelle, and the contexts it was used in, including the influence of Charles Darwin’s ‘tree diagrams’, and the context of Stamm, concluding with how Haeckel’s understanding of development led him to identify certain cells as ‘stem cells’. Inevitably, the term was not used consistently the first years following its conception, however by the early twentieth century, a clear ‘stem cell concept’ was developing. By the end of the nineteenth century, there were more sophisticated tools and techniques available to carry out experimental embryology, and an emerging stem cell concept. The last part of this presentation will consider how these merged to pave the way for the first descriptions of embryonic stem cells. This includes consideration of Wilhelm Roux’s ‘pricking experiments’, Hans Driesch’s work with sea urchin embryonic cells, and a short examination of American research (focussing on cell lineage).