This paper analyzes the answer given by Pasteur to those who defended the spontaneous generation theory and evaluates the impact these arguments had on the history of public hygiene. Because of that, the article emphasizes transmission of germs, rather than the origin of life, which has been quite analyzed. It also discusses the criticism Pasteur made to naturalists' arguments and tries to show that it is possible to say there is a certain continuity between the air-related concerns on the part of classic hygienists, most of which infectionists, and Pasteur's concern with germs spread in the air.
heterogenism; aerism; spontaneous generation; infectionists and contagionists