John Snow traces cholera to the Broad Street pump
- Date
- 1854
- Category
- Science, technology & invention
- Region
- Britain (London)
- Era
- Modern
- Significance
During a severe cholera outbreak that struck the Soho district of London from late August 1854, killing more than 600 people, the physician John Snow conducted a pioneering epidemiological investigation.
Sceptical of the prevailing miasma theory that blamed 'bad air', Snow mapped the addresses of the dead and interviewed survivors, finding that nearly all the victims drew their drinking water from a single public pump on Broad Street. On 7 September he persuaded local officials to remove the pump handle, and the outbreak subsided. By using spatial mapping and statistical reasoning to link disease to contaminated water, Snow demonstrated that cholera was a waterborne infection years before the responsible microbe was identified or germ theory was established. His work is widely regarded as a foundational moment in the science of epidemiology and in modern public health, strengthening the case for sanitary reform, clean water supplies, and evidence-based investigation of disease.
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Empires active in 1854
- Russian Empire1721 CE – 1917 CE
- French Colonial Empire (Second)1830 CE – 1962 CE
- British Empire1583 CE – 1997 CE
- Qing Dynasty1636 CE – 1912 CE
- Spanish Empire1492 CE – 1976 CE
- Portuguese Empire1415 CE – 1999 CE
Related science, technology & invention events
- Darwin publishes On the Origin of Species24 November 1859
- Faraday discovers electromagnetic induction29 August 1831
- Third Plague Pandemic begins in Yunnan1855 (origin in Yunnan); global spread from 1894
- Maxwell formulates the theory of electromagnetism1865–1873
- Opening of the Suez Canal17 November 1869
- Bell Patents the Telephone1876
Also relevant
Further reading
The wider story
A Little History of Science
Warm, jargon-free tour of discovery from Babylonian stargazers to the genome.
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