Certain moments of historical change exhibit uncommon drama. This session examines three such episodes from 20th-century biology: the migration of physicists into biology, the emergence of bioweapons research, and the debate about domains in systematics. The cases offer an occasion for reflecting on factors shaping historical innovation at the intersection of disciplines, all against a backdrop of trends in 20th-century biology.

Tara Abraham, Dibner Institute for the History of Science and Technology
"From Physics to Biology: Nicolas Rashevsky and Mathematical Biophysics at the University of Chicago"

The migration of physicists into biology during the early twentieth century (specifically molecular biology) has been a topic of interest in the history and philosophy of biology, with the associated issues of the disciplinary authority of physics, the reduction of biological phenomena to physical terms, and the autonomy of biological science. This paper will explore the work of Nicolas Rashevsky (1899-1972), a Russian ÈmigrÈ theoretical physicist who developed a program in "mathematical biophysics" at the University of Chicago in the mid-1930s. Noting the complexity of many biological phenomena, Rashevsky argued that the methods of theoretical physics ñ namely mathematics ñ were needed to "simplify" complex processes such as cell division, growth, and neural activity. A maverick of sorts, Rashevsky was a conspicuous figure in the biological community during the 1930s and early 1940s, participating in several Cold Spring Harbor meetings, and receiving several years of funding from the Rockefeller Foundation. However, in contrast to other migrant physicists, such as Max Delbr¸ck, Rashevsky's approach to biology was almost entirely theoretical, and he eventually faced some resistance to his mathematical methods. In light of this, putting Rashevsky's work in context will lead to reflections not only on the relationship between physics and biology during the period, but to tensions within biology between theory and experiment.

Gerard Fitzgerald, Carnegie Mellon University
"The Visible Laboratory:Bacteriological Engineering and Bioweapons Research at LOBUND: 1928-1955"

The history of biological weapons research within the United States from the period beginning with the Second World War until the present day remains an unwritten chapter in the modern history of science. Beginning during World War II and continuing throughout the Cold War, biological warfare research involved the identification, isolation, modification, mass production, and detection of various biological organisms and viruses. Much like the atomic bomb, the creation of this new class of weapons depended upon the invention and integration of new and existing technological and scientific instruments, machines, techniques, and methodologies. This paper examines the technological development and evolution of the mechanical barrier (isolation) system designed by Professor James A. Reyniers of the Laboratory of Bacteriology at the University of Notre Dame (LOBUND) from 1928-1945. An analysis of the work carried out by Reyniers and his students allows insights in the larger scientific, technological, and institut--
Trained as a microbiologist at the University of Notre Dame, Reyniers approached biology more as an inventor and spent his career as a self-titled "bacteriological engineer," whose machine shop often dwarfed his laboratory. Reyniers, whose family owned and operated a machine tool and die manufacturing business in Chicago, incorporated his machine shop skills in designing and building instruments and tools which facilitated the handling of both germ free and highly pathogenic organisms. Originally designed in 1928 as an instrumental system to facilitate "germ-free" and pure culture work in bacteriology, the isolation machinery provided an experimental space free from possible external contamination. The system also provided the biological and medical researcher with an equally effective space for bacterial containment. Over a ten-year period Reyniers constructed a modular and portable isolation system which integrated mechanical air filtration, steam sterilization, and specially constructed chambers with pres---
This paper will examine both the developmental phases of research for isolator design and construction during the inter-war period (1928-1939) in addition to a primary analysis of military applications of this technology for biological weapons research (1943-1946). The utility of isolator design saw three major applications. Reyniers employed isolation units in his own group at the University of Notre Dame for the freeze-drying of typhus. Karl Meyer used isolators for naval research on plague at University of California at Berkeley. In addition, Theodore Rosebury who headed the Airborne Pathogen Laboratory at Camp Detrick, converted isolators into experimental cloud chambers to test Serratia Marcescens, Bacillus Globigii, Brucella Suis, Malleomyces Mallei, and Pasteurella Tularensis as possible air-borne biological weapons. Rosebury's work was especially important and was instrumental in early post war decision making on future biological weapons research projects.

Sherrie Lyons
"Thomas Kuhn is Alive and Well: The Evolutionary Relationships of Simple Life Forms -- A Paradigm Under Siege"

Many current philosophers and historians of science are critical of Kuhn's model of scientific change. However, the current controversy over whether 2 or 3 fundamental types of life forms exist follows Kuhn's model surprisingly well. Until the 1980s, all life was classified into two primary forms: eukaryotes and prokaryotes. Using molecular sequencing data, Carl Woese and co-workers suggested a third division should be made. The data suggested that a relatively little known group of bacteria, the archaebacteria constituted a fundamental third form of life. Woese's suggestion was accepted quite quickly, becoming the prevailing paradigm for classification of simple life forms. In the mid 1990s, Radhey S. Gupta and co-workers claimed that their analysis of sequence data supported the 2 domain hypothesis. Furthermore, this was more in line with interpretations based on gross morphology and physiology. The controversy over the classification of simple life forms may seem to be a purely technical debate over the analysis of protein and nucleic acid sequence data. However, it illustrates a variety of factors that come into play in evaluating evidence. The prestige of molecular biology played a large role in Woese's work being so quickly accepted. Gupta represented an "outsider" challenging the prevailing paradigm and he has had a harder time in making his views known and accepted. His position is still in the minority. However, he is making converts daily, particularly as more sequence data provides evidence in support of the detailed phylogeny he has proposed. The controversy ecompasses broader issues as well such as the aims of classification and the role of microorganisms in the biosphere. This case study provides a good example of a paradigm shift in the making.