The Doctor Who Took the Handle Off the Pump

On the evening of Thursday, 31 August 1854, in a basement flat on Broad Street in the Soho district of London, a six-month-old infant named Frances Lewis died of cholera. She had been sick since 28 August. Her mother had been washing her soiled diapers in a bucket of water from the family’s cellar and tipping the dirty water into a cesspool in the back yard. The cesspool was lined with brick that had been laid badly when the house was built around 1750. Some of the contents leaked, slowly, through a gap in the lining and through about four feet of London clay, into a brick-vaulted shaft three meters away. The shaft was the well that fed the public water pump at the corner of Broad and Cambridge Streets.

Over the next ten days, somewhere between 500 and 700 people who had drunk from the Broad Street pump died of cholera. The actual number is unknowable because hundreds more fled the neighborhood and died elsewhere. The recorded deaths in the immediate area peaked at 73 in a single twenty-four-hour period. The outbreak was the most concentrated cholera episode in Victorian London — more deaths per square meter than anywhere else, before or after.

The physician who figured out what was happening was John Snow, age 41, a London anesthesiologist with an unfashionable theory about how cholera spread. The instrument he used was a map.

What everyone thought

The Victorian medical establishment in 1854 believed cholera was an airborne disease, transmitted by miasma — bad smell, foul vapors, the fetid air that hung over polluted neighborhoods. This theory had a great deal of historical support and one very large empirical problem: cholera outbreaks were not correlated with where the smells were worst. A bad-smelling district might have no cholera. A clean-smelling district might be devastated by it. The miasma theory had to keep adding epicycles to explain away the discrepancies.

The chief proponent of the miasma theory in England was Edwin Chadwick, the influential sanitary reformer whose 1842 report on the sanitary condition of the labouring population had reshaped British public health policy. Chadwick’s intervention was to flush the cesspools and drains into the Thames — on the theory that getting the smell away from people’s homes would reduce disease. This was the policy that, four years after Broad Street, would produce the Great Stink of 1858.

Snow had spent most of his career building the alternative theory: that cholera was waterborne. He had written a short pamphlet about it in 1849, after the previous epidemic, and almost nobody had paid attention. The 1854 outbreak gave him the opportunity to assemble the evidence at a scale that would be hard to ignore.

What Snow did

He started on the morning of Sunday, 3 September 1854 — four days into the outbreak. The General Register Office in Somerset House recorded each cholera death by location. Snow, who lived nearby on Sackville Street, requisitioned the death certificates as they were filed. He plotted each death on a street map of the Golden Square neighborhood with a small bar drawn at the victim’s address. Stacked bars meant multiple deaths at the same address.

The pattern that emerged when he plotted thirty deaths was suggestive. When he plotted eighty it was conclusive. The deaths clustered tightly around the pump on Broad Street, fell off sharply with distance, and were almost completely absent from streets served by the other nearby pumps (one on Carnaby Street, one on Warwick Street, one on Rupert Street).

Snow needed to test the cluster. He did it by going door to door, with the help of a local curate named Henry Whitehead. He interviewed the surviving residents at every address where someone had died. He asked which pump they used. Most of the dead — and almost none of the survivors — had drunk from Broad Street.

The harder test was the exceptions. There was a workhouse on Poland Street, half a block from the pump, with 535 inmates, where only five deaths had occurred. Snow asked. The workhouse had its own well. There was a brewery at 50 New Street with 70 workers and no cholera deaths. He asked. The workers drank malt liquor at work and water from the brewery’s private well at home. Neither establishment used the Broad Street pump. Neither got cholera.

And the brewery’s owner, a man named Mr. Huggins, told Snow that one of his workers who lived in Hampstead had recently died of cholera, far from the outbreak’s centre. Snow checked. The dead woman, Mrs. Susannah Eley, was a wealthy widow who had grown up in Broad Street and so liked the taste of its water that she had her servant bring a bottle of it to her in Hampstead twice a week. The bottle had arrived on 31 August. She had drunk from it on 1 September and died on 2 September. Her niece, who visited from Islington and shared the water, also died.

This was the cleanest possible test. Two people had been killed by the Broad Street pump while living far away from any plausible miasma.

What he did with the evidence

On the evening of Thursday, 7 September 1854, Snow presented his data to the Board of Guardians of St James’s parish, which had emergency jurisdiction over Soho during the outbreak. He showed the map. He told them about the brewery, the workhouse, and the Hampstead widow. He asked them to remove the handle from the Broad Street pump.

The Board was skeptical. The miasma theory was orthodoxy; Snow’s waterborne theory was eccentric. But the outbreak had already killed several hundred people in a neighborhood half a mile from Parliament, and the Board members had no better idea. They agreed to remove the handle the following morning. The handle came off on Friday, 8 September 1854.

By 8 September, the outbreak was already in steep decline. Most of the population of the surrounding streets had either died, recovered, or fled. The number of new cases had peaked four days earlier. The removal of the handle did not stop the outbreak; the outbreak had largely stopped itself by exhausting the pool of vulnerable people who had drunk the water. This is the part of the story that is usually left out of the Snow legend. He did not save Soho. He explained Soho.

What the handle removal did was prevent a second wave. As neighborhood residents returned to their homes over the following weeks, they would have started drinking from the pump again, and the contamination — which was still continuing, because the leaking cesspool was still leaking — would have produced new cases. The pump stayed closed. The second wave never happened.

What followed

Whitehead, the curate, continued investigating for months after Snow. It was Whitehead who traced the original source — the death of baby Frances Lewis in the basement of 40 Broad Street, the soiled diapers, the leaking cesspool. His report, published in 1855, confirmed Snow’s reconstruction and added the index case that Snow had never identified.

The miasma theory took another twenty years to die. Even after Snow’s 1855 monograph On the Mode of Communication of Cholera — which is now considered one of the founding documents of epidemiology — the British public health establishment continued to insist that cholera was airborne. Chadwick continued to recommend flushing waste into the Thames. The breakthrough came from outside England, in 1883, when Robert Koch’s German team identified the cholera bacillus in samples from Egyptian patients. By then John Snow had been dead for twenty-five years.

The pump at Broad Street was reinstalled after the outbreak and ran for another four decades before being replaced. The original handle, removed in September 1854, was discarded.

A replica pump with a removable handle stands today at the corner of Broadwick and Lexington Streets in Soho, a few meters from where the original was. The handle is still removed. It was installed by the John Snow Society in 1992, in part as a memorial and in part because the surrounding neighborhood, by then, had become the site of a popular pub — the John Snow, on Broadwick Street — where epidemiologists from the nearby London School of Hygiene and Tropical Medicine sometimes drink, and where the irony of toasting a Victorian abstainer who proved that London’s water was deadly is, by general agreement, the point.