The cell theory—the thesis that all life is made up of one or more cells, the fundamental structural and physiological unit—is one of the most celebrated achievements of modern biological science. And yet from its very inception in the nineteenth century it has faced repeated criticism from some biologists. Why do some continue to criticize the cell theory, and how has it managed nevertheless to keep burying its undertakers? The answers to these questions reveal the complex nature of the cell (...) theory and the cell concept on which it is based. Like other scientific ‘laws’, the assertion that all living things are made of cells purchases its universality at the expense of abstraction. If, however, this law is regarded merely as a widely applicable empirical generalization with notable exceptions, it still remains too important to discard. Debate about whether the cell or the organism standpoint provides the more correct account of anatomical, physiological, and developmental facts illustrates the tension between our attempts to express the truth about reality in conceptual terms conducive to a unified human understanding. (shrink)

Summary In 1979, Robert C. Olby published an article titled ?Mendel no Mendelian??, in which he questioned commonly held views that Gregor Mendel (1822?1884) laid the foundations for modern genetics. According to Olby, and other historians of science who have since followed him, Mendel worked within the tradition of so-called hybridists, who were interested in the evolutionary role of hybrids rather than in laws of inheritance. We propose instead to view the hybridist tradition as an experimental programme characterized by a (...) dynamic development that inadvertently led to a focus on the inheritance of individual traits. Through a careful analysis of publications on hybridization by Carl Linnaeus (1707?1778), Joseph Gottlieb Koelreuter (1733?1806), Carl Friedrich Gärtner (1772?1850), and finally Mendel himself, we will show that this development consisted in repeated reclassifications of hybrids to accommodate anomalies, which in the end allowed Mendel to draw analogies between whole organisms, individual traits, and ?elements? contained in reproductive cells. Mendel's achievement was a product of normal science, and yet a revolutionary step forward. This also explains why, in 1900, when the report he gave on his experiments was ?rediscovered?, Mendel could be read as a ?Mendelian? (shrink)

Edmund Beecher Wilson is generally celebrated for his contribution to chromosome theory and genetics, whereas opinion concerning his cytological thinking is often restricted to the idea that he provided evidence for the dominant role of the nucleus. But Wilson's cell theory was much more. It was a child of the German Zellforschung, and its attempt to provide a comprehensive cellular answer to a wide range of biological and physiological questions. Wilson developed a corpuscular, micromeristic and preformistic concept, and treated the (...) cell as an organism subject to ontogenetic and phylogenetic processes. He defended his comprehensive theory even in the 1920's, when cytological research had become specialised and directed at more practical goals. For many of his younger readers this concept might have seemed antiquated, but today many of its features sound surprisingly modern. (shrink)

In 1853, the young Thomas Henry Huxley published a long review of German cell theory in which he roundly criticized the basic tenets of the Schleiden-Schwann model of the cell. Although historians of cytology have dismissed Huxley's criticism as based on an erroneous interpretation of cell physiology, the review is better understood as a contribution to embryology. "The Cell-theory" presents Huxley's "epigenetic" interpretation of histological organization emerging from changes in the protoplasm to replace the "preformationist" cell theory of Schleiden and (...) Schwann (as modified by Albert von Kölliker), which posited the nucleus as the seat of organic vitality. Huxley's views influenced a number of British biologists, who continued to oppose German cell theory well into the twentieth century. Yet Huxley was pivotal in introducing the new German program of "scientific zoology" to Britain in the early 1850s, championing its empiricist methodology as a means to enact broad disciplinary and institutional reforms in British natural history. (shrink)

The ArgumentMicroscopical consideration played a crucial role in German physiology in the period of, grosso modo, 1780–1830. Specifically, a conception of material change was established, according to which all life is grounded in the process of the generation of microscopical forms out of an amorphous, primitive generative substance. Embryological development, tissue growth, and the generation of microorganisms were all considered to be the manifestation of this fundamental developmental process. In contrast to the common historiography, I try to understand Theodor Schwann's (...) 1838 discovery of the cell theory in terms of the epistemological categories he applied to the prevailing conceptions of life and living matter. I argue that Schwann was able to discern cells not because of any superior microscopical methods, but rather as part of his wider investigative endeavor to explicate life processes according to specific causal agents. I argue that Schwann was able to demonstrate the existence of cells only when he considered animal tissues in terms of a causal relation between specific material agents and their effect, that is, the developmental history of tissue. (shrink)

The term ‘cell’, in addition to designating fundamental units of life, has also been applied since the nineteenth century to technical apparatuses such as fuel and galvanic cells. This paper shows that such technologies, based on the electrical effects of chemical reactions taking place in containers, had a far-reaching impact on the concept of the biological cell. My argument revolves around the controversy over oxidative phosphorylation in bioenergetics between 1961 and 1977. In this scientific conflict, a two-level mingling of technological (...) culture, physical chemistry and biological research can be observed. First, Peter Mitchell explained the chemiosmotic hypothesis of energy generation by representing cellular membrane processes via an analogy to fuel cells. Second, in the associated experimental scrutiny of membranes, material cell models were devised that reassembled spatialized molecular processes in vitro. Cells were thus modelled both on paper and in the test tube not as morphological structures but as compartments able to perform physicochemical work. The story of cells and membranes in bioenergetics points out the role that theories and practices in physical chemistry had in the molecularization of life. These approaches model the cell as a ‘topology of molecular action’, as I will call it, and it involves concepts of spaces, surfaces and movements. They epitomize an engineer’s vision of the organism that has influenced diverse fields in today’s life sciences. (shrink)

In The Logic of Life François Jacob looks at the way our understanding of biology has changed since the sixteenth century. He describes four fundamental turning points in the perception of the structure of living things: the discoveries of the functions of organs, cells, chromosomes and genes, and DNA.