The entry keeps the Broad Street pump to one paragraph, because it is not the subject. But it happened in the middle of the south London inquiry, to the same man, and the official reaction to it is the clearest illustration there is of what the entry is about: an inquiry whose numbers were not disputed and whose conclusion was declined. This piece tells it in Snow’s words and the committees’ words, and nothing else.

Three days

The outbreak began on the night of 31 August 1854, in the streets around Golden Square on the north side of the river, a district supplied by the Grand Junction Company’s piped water and by a number of street pumps. Richardson’s account, written four years later, gives the scale: “Within two hundred and fifty yards of the spot where Cambridge-street joins Broad-street, there were upwards of five hundred fatal attacks of cholera in ten days.” Snow’s own table, built from the registrars’ returns, has 143 people attacked on 1 September, 116 on the 2nd, and 54 on the 3rd, and then a fall every day.

Snow was at that moment three weeks into his house-to-house inquiry south of the river. He left it. He went to the General Register Office for the deaths registered in the sub-districts of Golden Square, Berwick Street and St Ann’s in the week ending 2 September, found eighty-nine, of which eighty-three had happened in the last three days of the week, and marked each on a map. Nearly all lay within a short walk of the pump in Broad Street. The few that lay outside had reasons: two children who went to school near the pump and drank from it; a household that “always sent to the pump in Broad Street, as they preferred the water to that of the pump which was nearer.”

Within the pump’s own ground he asked at every house. “There were sixty-one instances in which I was informed that the deceased persons used to drink the pump-water from Broad Street, either constantly or occasionally. In six instances I could get no information, owing to the death or departure of every one connected with the deceased individuals; and in six cases I was informed that the deceased persons did not drink the pump-water before their illness.”

“The result of the inquiry then was, that there had been no particular outbreak or increase of cholera, in this part of London, except among the persons who were in the habit of drinking the water of the above-mentioned pump-well.”

Thursday 7 September

“I had an interview with the Board of Guardians of St. James’s parish, on the evening of Thursday, 7th September, and represented the above circumstances to them. In consequence of what I said, the handle of the pump was removed on the following day.”

That is the whole of Snow’s account of the famous evening. Richardson’s is longer and warmer. The vestrymen “were sitting in solemn consultation on the causes of the visitation,” in a panic such as London had perhaps not known “since the days of the great plague,” when “a stranger had asked, in modest speech, for a brief hearing.” He “advised the removal of the pump-handle as the grand prescription. The vestry was incredulous, but had the good sense to carry out the advice. The pump-handle was removed, and the plague was stayed.”

Snow did not say the plague was stayed. He said the opposite, in the sentence that matters most in this piece. “On September the 8th, the day when the handle of the pump was removed, there were twelve attacks; on the 9th, eleven; on the 10th, five; on the 11th, five; on the 12th, only one; and after this time, there were never more than four attacks on one day.” The mortality had been cut by the flight of the population, which began almost at once, “but the attacks had so far diminished before the use of the water was stopped, that it is impossible to decide whether the well still contained the cholera poison in an active state, or whether, from some cause, the water had become free from it.”

He had found, in other words, a strong association between drinking from one well and dying, and he had removed the well, and he could not show that removing it had done anything, because the outbreak was over before he acted. He wrote this down himself in the book he was trying to persuade people with.

The two committees

The parish of St James appointed a committee of inquiry, on which Snow sat with the curate of the district, Henry Whitehead, the surgeon J. G. French, Edwin Lankester and others. Whitehead began, as The Lancet told it in November 1855, as a doubter who set out “to take an ingenious investigator off a false scent,” and spent “many hours a day for a period of three months” on Broad Street alone, and came out “himself convinced that but for this source of water supply, the deaths from cholera, instead of amounting to 700, would not have reached 50.” The parish surveyor, Jehoshaphat York, found that the well’s brickwork stood within a few feet of a cesspool.

The committee’s finding, adopted on 25 July 1855 and presented to the vestry on 9 August, was that it “is unanimously of opinion that the striking disproportionate mortality in the ‘Cholera area,’ as compared with the immediately surrounding districts,” which it called “the sudden, severe and concentrated outbreak beginning on August 31st and lasting for the few early days of September, was in some manner attributable to the use of the impure water of the well in Broad Street.” It added that it found support “from the gradually accumulating evidence collected in other localities, as to the important influence of contaminated water in increasing cholera, especially in the districts of the metropolis lying south of the Thames,” and quoted the Registrar-General’s sentence about the balance of mortality.

The General Board of Health’s Committee for Scientific Inquiries, reporting a fortnight earlier, on 14 July, had found the district “offensive with effluvia from ill-conditioned sewers,” its houses “almost universally affected in the same manner,” its inhabitants “overcrowded, perhaps to the greatest degree known even in London,” and its air, by the reporters’ account, hazy, “singularly stagnant, sultry, and oppressive.” On that showing, it wrote, “any person conversant with the laws of disease might have predicted its extreme liability to suffer what afterwards befel it.” Why it suffered so much worse than districts no cleaner was “a difficulty which hitherto we have no scientific material to solve.”

Of the pump it wrote: “In explanation of the remarkable intensity of this outbreak within very definite limits, it has been suggested by Dr. Snow, that the real cause of whatever was peculiar in the case lay in the general use of one particular well, situate at Broad Street in the middle of the district, and having (it was imagined) its waters contaminated with the rice-water evacuations of cholera patients. After careful inquiry, we see no reason to adopt this belief. We do not find it established that the water was contaminated in the manner alleged; nor is there before us any sufficient evidence to show, whether inhabitants of the district, drinking from that well, suffered in proportion more than other inhabitants of the district who drank from other sources.”

It allowed one case in which the water had probably “really” acted as a vehicle, and explained even that away: “if the Broad Street pump did actually become a source of disease to persons dwelling at a distance, we believe that this may have depended on other organic impurities than those exclusively referred to, and may have arisen, not in its containing choleraic excrements, but simply in the fact of its impure waters having participated in the atmospheric infection of the district.” The Board’s microscopist, Hassall, had examined two samples from the well and found “no peculiar body or production” in either “calculated to excite suspicion,” only enough animalcules “to show that the water was not in a pure condition.”

John Simon, a year later, with the south London numbers in front of him, still put the pump at arm’s length. The St James’s committee’s evidence “strongly tends to justify their opinion,” he wrote, but “other and obvious facts give to the imputed operation at least an exceptional character,” because every shallow well in London was as foul, and a professor in Munich had been unable to connect that city’s wells with its cholera.

Why it is not the subject

The pump is the better story and the worse experiment. One well, one district, one week; no count of the people who drank from it and lived; a remedy applied after the outbreak had passed its peak, by the admission of the man who applied it; and a rival explanation, the stagnant air of the most crowded streets in London, that the Board could hold without contradiction from anything the pump showed. Snow’s evidence for it was good and he said what it could not prove.

The pipes were the worse story and the better experiment. Three hundred thousand people in two groups, with nothing to choose between them but the company’s name on a receipt; a count of the living as well as the dead; and fourteen weeks of returns from an office that did not belong to him. The Board’s own chemist, looking at those returns, could not avoid the conclusion that the Southwark water had done something. The Board’s medical officer, with the street lists, measured it to the last house. And the Board, through both of them, kept the air. That is why the entry is about the pipes.

Sources

• John Snow, On the Mode of Communication of Cholera, second edition, London: John Churchill, 1855, the chapter on the cholera near Golden Square: the eighty-nine deaths of the week ending 2 September, the map, the children and the household that preferred the Broad Street water, the sixty-one and six and six, the interview of 7 September, the removal of the handle, the table of attacks by day, and “impossible to decide.” archive.org
• Benjamin Ward Richardson, “The Life of John Snow, M.D.,” prefixed to Snow’s On Chloroform and Other Anaesthetics, London, 1858: the five hundred fatal attacks in ten days, the vestry in solemn consultation, “a stranger had asked, in modest speech, for a brief hearing,” and “the plague was stayed.” archive.org
• Cholera Inquiry Committee, Report on the Cholera Outbreak in the Parish of St. James, Westminster, during the Autumn of 1854, London: John Churchill, 1855: the unanimous finding, the support drawn from the south London returns, and the committee’s members and dates. archive.org
• General Board of Health, Medical Council, Report of the Committee for Scientific Inquiries in relation to the Cholera-Epidemic of 1854, London, 1855: the description of the district, “we see no reason to adopt this belief,” the participation in “the atmospheric infection of the district,” and Hassall’s examination of the pump water in the appendix. archive.org
• John Simon, Report on the Last Two Cholera-Epidemics of London, as Affected by the Consumption of Impure Water, London, 1856, page 11: “at least an exceptional character” and the Munich inquiry. archive.org
• The Lancet, 24 November 1855, review of Snow’s book and the St James’s report: Whitehead’s three months on Broad Street, the 700 and the 50, and York’s finding of the cesspool. archive.org