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John Snow Memorial

In 1854, York-born physician John Snow confirmed the link between cholera and polluted water by removing the handle of a communal water pump in London's Soho.

The memorial was officially unveiled in North Street Gardens on March 15th, 2017. It takes the form of a typical 19th century water pump, with its handle removed and lying loosely on the ground beside the pump (see Image 1 below).

John Snow was born in nearby North Street on March 15th, 1813. At that time, the area was one of the most deprived neighbourhoods in York. However, John Snow was very fortunate as he was granted a place at one of the city's 'common day schools'. These aimed to provide a basic education for selected children from poor families, although fees of some kind were still usually payable. John Snow attended the school for eight years and he was considered to be an intelligent and hard-working student.

After leaving the school at the age of 14, he served apprenticeships with:

  • William Hardcastle (a friend of the family who was a surgeon-apothecary in Newcastle-upon-Tyne and whose private clients included George Stephenson),
  • John Watson (an apothecary in the small village of Burnopfield, approximately ten miles southwest of Newcastle), and
  • Joseph Warburton (an apothecary in Pateley Bridge, West Yorkshire).

During the first of these apprenticeships, John Snow was sent to a colliery near the village of Killingworth, where there was an outbreak of cholera. This experience left a lasting impression on the young apprentice and it almost certainly set the seeds for his later investigations into the transmission of infectious diseases.

In the summer of 1836, John Snow returned to York for a brief period. During this time he played a role in the creation of the York Temperance Society.

In October 1836, at the age of 23, Snow began his formal medical education, starting with a year at the Great Windmill Street School (a.k.a. the Hunterian School of Medicine), which was located in the central London district of Soho, followed by a year at the Westminster Hospital. After passing his examinations in May 1838, John Snow became a Member of the Royal College of Surgeons of England. He then began to practice medicine as both an apothecary and a general practitioner.

Figure 1: Extract from John Snow's map showing the distribution of deaths during the 1854 cholera outbreak in the Broad Street area of London.Extract from John Snow's map showing the distribution of deaths during the 1854 cholera outbreak in the Broad Street area of London.

Tip: To view a larger version of the full map (809Kb), click / tap on the thumbnail above.

During the course of his career, John Snow become increasingly convinced that there was a link between deaths from cholera and the consumption of contaminated water. In 1854, a severe outbreak of cholera in the Broad Street area of Soho provided Snow with an opportunity to test his theory. He plotted each cholera-related death on a large scale street map (see Figure 1) and the resulting bar charts showed a very clear pattern: the highest death rates were centred on a single communal water pump located near the corner of Broad Street and Cambridge Street. The text below is John Snow's own account of the events.

The most terrible outbreak of cholera which ever occurred in this kingdom, is probably that which took place in Broad Street, Golden Square, and the adjoining streets, a few weeks ago. 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. The mortality in this limited area probably equals any that was ever caused in this country, even by the plague; and it was much more sudden, as the greater number of cases terminated in a few hours. The mortality would undoubtedly have been much greater had it not been for the flight of the population. Persons in furnished lodgings left first, then other lodgers went away, leaving their furniture to be sent for when they could meet with a place to put it in. Many houses were closed altogether, owing to the death of the proprietors; and, in a great number of instances, the tradesmen who remained had sent away their families: so that in less than six days from the commencement of the outbreak, the most afflicted streets were deserted by more than three-quarters of their inhabitants.

There were a few cases of cholera in the neighbourhood of Broad Street, Golden Square, in the latter part of August; and the so-called outbreak, which commenced in the night between the 31st August and the 1st September, was, as in all similar instances, only a violent increase of the malady. As soon as I became acquainted with the situation and extent of this irruption of cholera, I suspected some contamination of the water of the much frequented street-pump in Broad Street, near the end of Cambridge Street; but on examining the water, on the evening of the 3rd September, I found so little impurity in it of an organic nature, that I hesitated to come to a conclusion. Further inquiry, however, showed me that there was no other circumstance or agent common to the circumscribed locality in which this sudden increase of cholera occurred, and not extending beyond it, except the water of the above mentioned pump. I found, moreover, that the water varied, during the next two days, in the amount of organic impurity, visible to the naked eye, on close inspection, in the form of small white, flocculent particles; and I concluded that, at the commencement of the outbreak, it might possibly have been still more impure. I requested permission, therefore, to take a list, at the General Register Office, of the deaths from cholera, registered during the week ending 2nd September, in the subdistricts of Golden Square, Berwick Street, and St. Ann's, Soho, which was kindly granted. Eighty-nine deaths from cholera were registered, during the week, in the three subdistricts. Of these, only six occurred in the four first days of the week; four occurred on Thursday, the 31st August; and the remaining seventy-nine on Friday and Saturday. I considered, therefore, that the outbreak commenced on the Thursday; and I made inquiry, in detail, respecting the eighty-three deaths registered as having taken place during the last three days of the week.

On proceeding to the spot, I found that nearly all the deaths had taken place within a short distance of the pump. There were only ten deaths in houses situated decidedly nearer to another street pump. In five of these cases the families of the deceased persons informed me that they always sent to the pump in Broad Street, as they preferred the water to that of the pump which was nearer. In three other cases, the deceased were children who went to school near the pump in Broad Street. Two of them were known to drink the water; and the parents of the third think it probable that it did so. The other two deaths, beyond the district which this pump supplies, represent only the amount of mortality from cholera that was occurring before the irruption took place.

With regard to the deaths occurring in the locality belonging to the pump, 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.

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.

. . .

The greatest number of attacks in any one day occurred on the 1st of September, immediately after the outbreak commenced. The following day the attacks fell from one hundred and forty-three to one hundred and sixteen, and the day afterwards to fifty-four. A glance at the above table will show that the fresh attacks continued to become less numerous every day. 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. During the decline of the epidemic the deaths were more numerous than the attacks, owing to the decease of many persons who had lingered for several days in consecutive fever.

Source: "On the Mode of Communication of Cholera" by John Snow, M.D. Second Edition, London (1855), pages 38-40 and page 51.

A detailed and fascinating biography of John Snow is available online (see 'External Links' below).

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John Snow Memorial
North Street Gardens

Latitude: 53.958886000000
Longitude: -1.085857000000

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