Ludwik Fleck on the social construction of medical knowledge.

The subject of the development and transmission of medical knowledge has remained, until recently, relatively little studied by medical sociologists. But as early as the 1930s the pioneering studies of Ludwick Fleck, a physician and historian of science, dealt with the evolution of medical knowledge and the genesis of medical facts. Starting with a reflection on his own experience as clinical bacteriologist and immunologist, Fleck developed highly original views on subjects such as the influence of patterns of specialization of physicians on the medical knowledge they produced, the impact of popular models of disease on expert ones, and the importance of the circulation of ideas between distinct, and--according to Fleck--incommensurable 'thought collectives' (medical scientists, general practitioners and patients) for the development of innovations in medicine. The aim of this article is to analyze Fleck's vision of medicine and to select among his ideas those which may be of interest for sociologists of medicine today.