The Pump Handle and the Epidemic Already Fading

In the last days of August 1854, cholera struck a few crowded streets of Soho in London. Within about a week, hundreds of residents were dead, and many families had fled. The physician John Snow, who lived nearby, suspected that the disease did not travel through foul air, as most medical authorities then believed, but through water.

Snow questioned the families of the dead and marked their homes on a map. The deaths clustered around a public pump in Broad Street. On 8 September, he persuaded the local board of guardians to remove its handle. The outbreak soon ended, and the removal of the handle has since become one of the best known episodes in the history of public health.

The truth is more modest than the legend. The number of new cases had already begun to fall before the handle was taken away, probably because many residents had left and others had begun to avoid the well. Snow himself seems to have recognised this. His real achievement lay elsewhere, in his careful gathering of evidence and in showing, through patient comparison of households that drew water from different companies, that cholera followed the water supply.

The number of new cases had already begun to fall before the handle was taken away, probably because many residents had left and others had begun to avoid the well.

The authorities were not persuaded at once. A committee that reviewed the outbreak rejected Snow's theory, and the belief in bad air persisted for years. Only later, when the bacterium behind cholera was identified, was Snow's reasoning accepted as sound. His story reminds readers that a good method can be right long before the proof is complete, and that a famous gesture is often less important than the quiet work behind it.