numerous near to the pump where the water could be more readily obtained. There was one significant anomaly—none of the workers in the nearby Broad Street brewery contracted cholera. As they were given a daily allowance of beer, they did not consume water from the nearby well. During the brewing process, the wort (or un-fermented beer) is boiled in part so that hops can be added. This step killed the cholera bacteria in the water they had used to brew with, making it safe to drink. Snow showed that the Southwark and Vauxhall Waterworks Company was taking water from sewage-polluted sections of the Thames and delivering it to homes, resulting in an increased incidence of cholera among its customers. Snow's study is part of the history of public health and health geography. It is regarded as the founding event of epidemiology. In Snow's own words: On proceeding to the spot, I found that nearly all the deaths had taken place within a short distance of the [Broad Street] 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 pumps which were nearer. In three other cases, the deceased were children who went to school near the pump in Broad Street ... With regard to the deaths occurring in the locality belonging to the pump, there were 61 instances in which I was informed that the deceased persons used to drink the pump-water from Broad Street, either constantly or occasionally ... The result of the inquiry then was, that there had been no particular outbreak or prevalence 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, the 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. It was discovered later that this public well had been dug from an old cesspit that had begun to leak faecal bacteria. Waste water from washing nappies, used by a baby who had contracted cholera from another source, drained