Death and miasma in Victorian London: an obstinate belief
--Stephen Halliday, BMJ. 2001 December 22; 323(7327): 1469–1471.

“From inhaling the odour of beef the butcher's wife obtains her obesity.” Professor H Booth, writing in the Builder, July 1844

This assertion is perhaps the most extravagant manifestation of a belief that prevailed in the medical profession for much of the 19th century and survived in some quarters into the 20th century. This belief held that most, if not all, disease was caused by inhaling air that was infected through exposure to corrupting matter. Such matter might be rotting corpses, the exhalations of other people already infected, sewage, or even rotting vegetation. The “miasmatic” explanation of the cause of disease figured prominently in the long debates among the people who were responsible for combating the cholera epidemics that afflicted Britain, and particularly London, between 1831 and 1866.