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John Snow

1813–1858 · English

Medicine — epidemiology and anaesthesia

John Snow was a London physician regarded as a founder of modern epidemiology. During the 1854 Soho cholera outbreak he traced cases to the Broad Street water pump and persuaded the authorities to remove its handle, supporting his theory that cholera spreads through contaminated water rather than 'miasma'. He was also a pioneer of anaesthesia, giving chloroform to Queen Victoria during childbirth.

How to spot them

▸Broad Street pump, Soho, 1854; removing the pump handle
▸Cholera spread by water, not miasma (bad air); a map of cases
▸Chloroform for Queen Victoria at the births of Prince Leopold (1853) and Princess Beatrice (1857)
▸The 'Grand Experiment' comparing London water companies
▸Born in York; a teetotaller and vegetarian, remembered by a pub in Broadwick Street

Key discoveries & works

On the Mode of Communication of Cholera (1849; 2nd edition 1855)

Argued cholera was transmitted by contaminated water; the 2nd edition included his Soho map

Removal of the Broad Street pump handle (1854)

Traced the Soho cholera outbreak to a single public water pump

Map of cholera deaths in Soho (1854–1855)

Dot map showing deaths clustered around the Broad Street pump

The 'Grand Experiment' on London water supplies (1854)

Compared cholera deaths among customers of the Southwark and Vauxhall and Lambeth water companies

Chloroform given to Queen Victoria in childbirth (1853)

At the birth of Prince Leopold; again for Princess Beatrice in 1857

On Chloroform and Other Anaesthetics (1858)

Published shortly after his death

Key ideas

Cholera is caused by something ingested, spread via water contaminated with sewage, challenging the miasma theory
Systematic mapping and statistical comparison of cases as tools for tracing disease
Scientific dosing of ether and chloroform made anaesthesia safer

Quick-fire facts

•Born in York in 1813, the son of a labourer
•Broad Street in Soho is now Broadwick Street; a replica pump and the John Snow pub stand there
•The pump handle was removed on 8 September 1854, by which time the outbreak was already declining
•Queen Victoria's use of chloroform, 'chloroform à la reine', made anaesthesia in childbirth respectable
•Died in 1858 after a stroke and was buried in Brompton Cemetery

Drill it — 7 cards

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Sources

BBC History — John Snow (1813–1858)
Peter Vinten-Johansen et al. — Cholera, Chloroform, and the Science of Medicine: A Life of John Snow