In his essay "On the Mode of Communication of Cholera," John Snow constructs his own theories to replace the prevailing notions about the causes and transmission of cholera. His analysis begins with findings from other physicians who reported cases in which people died of cholera after staying in a room that was previously occupied by a disease-stricken person:
Now the next case of cholera, in London, occurred in the very room in which the above patient died. A man named Blenkinsopp came to lodge in the same room. He was attacked with cholera on the 30th September . . .
He continues to support his theory by describing the pathology of cholera. He rejects the notion that cholera can be transmitted through the air, noting that people who attend to patients with cholera do not necessarily become sick with the disease. He describes symptoms to support his claim that cholera afflicts the alimentary canal.
Finally, Snow uses details from his own experience with an outbreak on Broad Street to support his claim. He explains how individuals using the same water pump became ill with the disease. Snow relies on documentary evidence to show how water from the Broad Street pump was linked to patients with cholera.
