The Extension of the Germ Theory to the Etiology of Certain Common Diseases

On 3 May 1880, Louis Pasteur stood before the French Academy of Sciences and argued that the living microbes he had shown to drive fermentation also caused certain common diseases. This is that argument, in the contemporary English translation of H. C. Ernst, M.D. - a primary witness to the germ theory mid-passage, confident enough to assert and contested enough to require the assertion. The period vocabulary is preserved, including the older sense of virus. When Pasteur read this paper to the French Academy of Sciences in May 1880, the idea that invisible living organisms caused disease was neither obvious nor settled. It was contested, and Pasteur was one of its principal architects. The germ theory of disease holds that many illnesses are caused by specific microorganisms, each disease the work of a particular living agent that can be transmitted, cultured, and in principle defeated. This source edition reproduces the paper in full with an editorial apparatus that places it in the contested passage from a chemical and miasmatic understanding of illness to a microbial one.