Images of cell trees, cell lines, and cell fates: the legacy of Ernst Haeckel and August Weismann in stem cell research

• Published in: History and philosophy of the life sciences Vol. 36; no. 2; pp. 157 - 186
• Main Author: Dröscher, Ariane
• Format: Journal Article
• Language: English
• Published: Cham Springer 2014; Springer International Publishing
• Subjects: Biology; Cell Biology - history; Cell Line; Cell lines; Cells; Cellular differentiation; Diagrams; Education; Embryology; Embryonic stem cells; Germ cells; Germany; Haeckel; History of medicine and histology; History of Science; History, 19th Century; Life Sciences; Original Paper; Philosophy; Philosophy of Biology; Philosophy of Science; Somatic cells; Stem Cell Research - history; Stem Cells; Weismann; Germany; Metaphors; August Weismann; Hematopoiesis; Tree of cells; Ernst Haeckel; Stem cells
• ISSN: 0391-9714; 1742-6316
• DOI: 10.1007/s40656-014-0028-8

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.