Source 13 - John Snow's Cholera map

John Snow was born in York in 1813. He moved to London in 1836 to begin his medical education, graduating in 1844.

At that time, in London and across the country, outbreaks of cholera were widespread. It was believed to be an air-borne disease. However, Snow did not accept this theory and set out his own ideas in his work On the Mode of Communication of Cholera, published in 1849. Snow was able to further investigate his theories in 1854, during an outbreak of cholera in London. By plotting deaths as they occurred on a map, he was able to identify a pump on a road called Broad Street, as the common factor to them all. When the handle of the pump was removed, cases of cholera immediately began to diminish.

This extract introduces the case of the Broad Street Pump in Snow's On the Mode of Communication of Cholera, reprinted in 1855.

  • What factors do you think may have contributed to there being so many deaths in the case of the Broad Street Pump? You might like to look at source 12 to help you.
  • Why do you think Snow decided to present his findings using a map?
  • What does the case of the Broad Street Pump tell you about the importance of research, investigation and enquiry when planning and running a campaign?

Taken from: On the Mode of Communication of Cholera
Author / Creator: John Snow
Date: 1855
Copyright: By permission of the British Library Board