Contingent contagionism

Contingent contagionism was a concept in 19th-century medical writing and epidemiology before the germ theory, used as a qualified way of rejecting the application of the term "contagious disease" for a particular infection. For example, it could be stated that cholera, or typhus, was not contagious in a "healthy atmosphere", but might be contagious in an "impure atmosphere". Contingent contagionism covered a wide range of views between "contagionist", and "anti-contagionist" such as held by supporters of the miasma theory.

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