Abstract

The conception of contagious disease that Girolamo Fracastoro provides in his work De contagione et contagiosis morbis, marks the origin of modern epidemiology and microbiology. This conception puts into play the Galenic and Aristotelian traditions of research, faced with its own conceptual limitations of the growing mechanistic thought of the time. According to Fracastoro, epidemic diseases spread by invisible living germs called seminaria, begotten by corrupted humours. Fracastoro resorted to the old notions of "sympathy" and "antipathy" to respond to questions about how seminaria is transmitted from one body to another, and what is the specificity that limits its transmission to certain species and organs. Like Galileo and Descartes, Fracastoro tries to establish a dialogue in the field of medicine between the Aristotelian vitalism and the modern mechanistic perspective. The purpose of this paper is to highlight the ideological, theoretical and conceptual assumptions, both philosophical and scientific, assumed by Fracastoro with regard to the problem of contagion.