It is now twenty years since James Watson published his personal account of the discovery of the structure of DNA and triggered the growing scholarly study of the roots of molecular biology. Watson himself was not concerned with the study of nucleic acids before he became directly involved but at least three detailed histories of the early development of molecular biology have subsequently appeared, together with books, papers and reviews from others who took part, or their partisan representatives. Of these (...) three histories, only one does justice to Avery's work. His surviving DNA collaborator, MacLyn McCarty, believes that only Olby inThe Path to the Double Helixdeals adequately with Avery's contribution. (shrink)

The role of bacterial variation in the waxing and waning of epidemics was a subject of lively debate in late nineteenth and early twentieth-century bacteriology and epidemiology. The notion that changes in bacterial virulence were responsible for the rise and fall of epidemic diseases was an often-voiced, but little investigated hypothesis made by late nineteenth-century epidemiologists. It was one of the first hypotheses to be tested by scientists who attempted to study epidemiological questions using laboratory methods. This paper examines how (...) two groups of experimental epidemiologists, the British group led by W. W. C. Topley and Major Greenwood, and an American group directed by Leslie T. Webster at the Rockefeller Institute, studied the role of variations in bacterial virulence in the course of laboratory epidemics of mouse typhoid. Relying on Ludwik Fleck’s concept of thought styles and thought collectives, the paper analyzes the fundamental conceptual differences between these two groups of researchers and analyzes the kinds of innovations they introduced as they attempted to integrate bacteriological and epidemiological approaches. The paper shows that the stylistic differences between the two groups can be understood better in the context of the institutional histories and disciplinary relations of epidemiology and bacteriology in the two countries. (shrink)

This essay attempts to describe the neo-Lamarckian atmosphere that was dominant in French biology for more than a century. Firstly, we demonstrate that there were not one but at least two French neo-Lamarckian traditions. This implies, therefore, that it is possible to propose a clear definition of a (neo) Lamarckian conception, and by using it, to distinguish these two traditions. We will see that these two conceptions were not dominant at the same time. The first French neo-Lamarckism (1879-1931) was structured (...) by a very mechanic view of natural processes. The main representatives of this first period were scientists such as Alfred Giard (1846-1908), Gaston Bonnier (1853-1922) and Félix Le Dantec (1869-1917). The second Lamarckism - much more vitalist in its inspiration - started to develop under the supervision of people such as Albert Vandel (1894-1980) and Pierre-Paul Grassé (1895-1985). Secondly, this essay suggests that the philosophical inclinations of these neo-Lamarckisms reactivated a very ancient and strong dichotomy of French thought. One part of this dichotomy is a material, physicalist tradition, which started with René Descartes but developed extensively during the 18th and 19th centuries. The other is a spiritual and vitalist reaction to the first one, which also had a very long history, though it is most closely associated with the work of Henri Bergson. Through Claude Bernard, the first neo-Lamarckians tried to construct a mechanical and determinist form of evolutionary theory which was, in effect, a Cartesian theory. The second wave of neo-Lamarckians wanted to reconsider the autonomy and reactivity of life forms, in contrast to purely physical systems. (shrink)

This essay attempts to describe the neo-Lamarckian atmosphere that was dominant in French biology for more than a century. Firstly, we demonstrate that there were not one but at least two French neo-Lamarckian traditions. This implies, therefore, that it is possible to propose a clear definition of a (neo)Lamarckian conception, and by using it, to distinguish these two traditions. We will see that these two conceptions were not dominant at the same time. The first French neo-Lamarckism (1879–1931) was structured by (...) a very mechanic view of natural processes. The main representatives of this first period were scientists such as Alfred Giard (1846–1908), Gaston Bonnier (1853–1922) and Félix Le Dantec (1869–1917). The second Lamarckism – much more vitalist in its inspiration – started to develop under the supervision of people such as Albert Vandel (1894–1980) and Pierre-Paul Grassé (1895–1985). Secondly, this essay suggests that the philosophical inclinations of these neo-Lamarckisms reactivated a very ancient and strong dichotomy of French thought. One part of this dichotomy is a material, physicalist tradition, which started with René Descartes but developed extensively during the 18th and 19th centuries. The other is a spiritual and vitalist reaction to the first one, which also had a very long history, though it is most closely associated with the work of Henri Bergson. Through Claude Bernard, the first neo-Lamarckians tried to construct a mechanical and determinist form of evolutionary theory which was, in effect, a Cartesian theory. The second wave of neo-Lamarckians wanted to reconsider the autonomy and reactivity of life forms, in contrast to purely physical systems. (shrink)

: This article analyzes German debates on the microbiology of infectious diseases from 1865 to 1875 and asks how and when organic pollution in tissues became noteworthy for aetiology and pathogenesis. It was with Ernst Hallier's pleomorphistic microbiology that the organic character of alien material in tissues came to be regarded as important for pathology. The process that followed saw both vigorous biological critique and a number of medical applications of Hallier's work. Around 1874 contemporaries reached the conclusion that pleomorphous (...) vegetation was most likely of little importance if not accidental in relation to the aetiology of infectious diseases whereas the idea of monomorphous micro-organisms facilitated a causal explanation. It was only then that notions such a pure cultures, bacterial specificity, etc. favored by Ferdinand Julius Cohn and his school became popular in medical circles. (shrink)

In this paper I present a model of rational belief change, and I show how to use it to obtain a better insight into the debate about the nature of pneumococcal transformation, genes and DNA that took place in the forties, as a result of Oswald T. Avery’s work. The model offers a particular elaboration of the concept of inference to the best explanation, along decision theoretic lines. Within this framework, I distinguish different senses in which Avery’s team can be (...) said to have proceeded with caution, thus throwing some light upon a persistent source of disagreement among researchers in the history of genetics. In addition, I explain why we are entitled to say that rival parties such as physicist Maclyn McCarty and biochemist Alfred Mirsky were epistemically rational, in spite of the fact that they reached different conclusions on the basis of the same evidence. (shrink)

Although epidemiology as a scientific study of disease in populations claimed an independent disciplinary status already in the mid–nineteenth century, its history in the twentieth century can be seen as a continuous and often contentious attempt to define the field’s social and intellectual boundaries vis-à-vis a variety of neighboring scientific fields and public health practices. In a period dominated by laboratory biomedical sciences, epidemiologists repeatedly tried to spell out how their discipline met the requirements of scientificity despite its focus on (...) disease as a collective phenomenon and its reliance on nonlaboratory methods. This article asks about the relationship between the changing institutional and intellectual contexts of British epidemiological practice and the epidemiologists’attempts to define both science in general and epidemiology in particular. An examination of the epidemiologists’boundary-making endeavors is also used to reflect on the circumstances in which scientists engage in the discourse of disciplinary demarcations. (shrink)

The role of bacterial variation in the waxing and waning of epidemics was a subject of lively debate in late nineteenth and early twentieth-century bacteriology and epidemiology. The notion that changes in bacterial virulence were responsible for the rise and fall of epidemic diseases was an often-voiced, but little investigated hypothesis made by late nineteenth-century epidemiologists. It was one of the first hypotheses to be tested by scientists who attempted to study epidemiological questions using laboratory methods. This paper examines how (...) two groups of experimental epidemiologists, the British group led by W. W. C. Topley and Major Greenwood, and an American group directed by Leslie T. Webster at the Rockefeller Institute, studied the role of variations in bacterial virulence in the course of laboratory epidemics of mouse typhoid. Relying on Ludwik Fleck’s concept of thought styles and thought collectives, the paper analyzes the fundamental conceptual differences between these two groups of researchers and analyzes the kinds of innovations they introduced as they attempted to integrate bacteriological and epidemiological approaches. The paper shows that the stylistic differences between the two groups can be understood better in the context of the institutional histories and disciplinary relations of epidemiology and bacteriology in the two countries. (shrink)

The 1940s and 1950s were marked by intense debates over the origin of drug resistance in microbes. Bacteriologists had traditionally invoked the notions of ‘training’ and ‘adaptation’ to account for the ability of microbes to acquire new traits. As the field of bacterial genetics emerged, however, its participants rejected ‘Lamarckian’ views of microbial heredity, and offered statistical evidence that drug resistance resulted from the selection of random resistant mutants. Antibiotic resistance became a key issue among those disputing physiological vs. genetic (...) explanations of variation in bacteria. Postwar developments connected with the Lysenko affair gave this debate a new political valence.Proponents of the neo-Darwinian synthesis weighed in with support for the genetic theory. However, certain features of drug resistance seemed inexplicable by mutation and selection, particularly the phenomenon of ‘multiple resistance’—the emergence of resistance in a single strain against several unrelated antibiotics. In the late 1950s, Tsutomu Watanabe and his collaborators solved this puzzle by determining that resistance could be conferred by cytoplasmic resistance factors rather than chromosomal mutation. These R factors could carry resistance to many antibiotics and seemed able to promote their own dissemination in bacterial populations. In the end, the vindication of the genetic view of drug resistance was accompanied by a recasting of the ‘gene’ to include extrachromosomal hereditary units carried on viruses and plasmids. (shrink)

The sociological dimension of science is studied using the discovery of the Wasserman reaction and its accidental application as a test for syphilis as a basis, ...

The episodes of cowpox inoculation (1798) and rabies preventive treatment (1885) are celebrated as the landmark of modern medicine. Paradoxically, these two advances have been accomplished without any theoretical breakthrough in the understanding of immunity. Going further, they were made possible by a long past of empirical procedures among which smallpox inoculation played an outstanding role. The paper explores the paradox of 'Immunization without Immunology' and Pasteur's reconstruction of the past, through his successful use of a metaphor. 'Vaccine', originally linked (...) to the jennerian method, was meant by Pasteur to designate a general program of virus attenuation. The paper investigates the scientific factors accounting for why viruses played such a leading role in immunization. The longlasting immunity, the easy transmission from man to man characteristic of smallpox allowing in vivo experimentation, may explain how crude procedures of early immunizers shaped scientific ideologies and strategies of public health and finally initiated modern 'vaccinology'. (shrink)

Avery’s et al. ’s 1944 paper provides the first direct evidence of DNA having gene-like properties and marks the beginning of a new phase in early molecular genetics (with a strong focus on chemistry and DNA). The study of its reception shows that on the whole, Avery’s results were immediately appreciated and motivated new research on transformation, the chemical nature of DNA’s biological specificity and bacteria genetics. It shows, too, that initial problems of transferring transformation to other systems and prominent (...) criticism of its results nurtured skepticism. Avery’s experiment was downplayed and neglected particularly by many of those scientists who worked in the new fields of biochemical and biophysical genetics, genetic phage, and TMV research. This was not due to the fact that the implications of the paper could not be connected to generally accepted knowledge. Contrary to a widespread belief, the assumed uniformity of DNA as opposed to proteins was not used as an argument against the validity of Avery’s et al.’s finding. The indifference rather reflected, among other things, the disciplinary gap between the chemically oriented microbiologists and the old and new geneticists who remained committed to genetic and physical methods (in particular x-ray studies) and clung to the assumption that proteins were the sole carriers of biological specificity. The responses to Avery’s et al.’s paper show how different research interests in the areas between microbiology, genetics, and biochemistry interacted with the prejudices, dogmas, individual farsightedness or short-sightedness, and scientific authority during a pivotal period of early molecular biology. (shrink)

The chemical characterization of the substance responsible for the phenomenon of “transformation” of pneumococci was presented in the now famous 1944 paper by Avery, MacLeod, and McCarty. Reception of this work was mixed. Although interpreting their results as evidence that deoxyribonucleic acid (DNA) is the molecule responsible for genetic changes was, at the time, controversial, this paper has been retrospectively celebrated as providing such evidence. The mixed and changing assessment of the evidence presented in the paper was due to the (...) work’s interpretive flexibility – the evidence was interpreted in various ways, and such interpretations were justified given the neophytic state of molecular biology and methodological limitations of Avery’s transformation studies. I argue that the changing context in which the evidence presented by Avery’s group was interpreted partly explains the vicissitudes of the assessments of the evidence. Two less compelling explanations of the reception are a myth-making account and an appeal to the wartime historical context of its publication. (shrink)