<P> Snow later used a dot map to illustrate the cluster of cholera cases around the pump . He also used statistics to illustrate the connection between the quality of the water source and cholera cases . He showed that the Southwark and Vauxhall Waterworks Company was taking water from sewage - polluted sections of the Thames and delivering the water to homes, leading to an increased incidence of cholera. Snow's study was a major event in the history of public health and geography . It is regarded as one of the founding events of the science of epidemiology . </P> <P> Later, researchers discovered that this public well had been dug only three feet from an old cesspit, which had begun to leak fecal bacteria . The diapers of a baby, who had contracted cholera from another source, had been washed into this cesspit . Its opening was originally under a nearby house, which had been rebuilt farther away after a fire . The city had widened the street and the cesspit was lost . It was common at the time to have a cesspit under most homes . Most families tried to have their raw sewage collected and dumped in the Thames to prevent their cesspit from filling faster than the sewage could decompose into the soil . </P> <P> After the cholera epidemic had subsided, government officials replaced the handle on the Broad Street pump . They had responded only to the urgent threat posed to the population, and afterward they rejected Snow's theory . To accept his proposal would have meant accepting the fecal - oral method transmission of disease, which they dismissed . </P> <P> The more formal experiments on the relationship between germ and disease were conducted by Louis Pasteur between 1860 and 1864 . He discovered the pathology of the puerperal fever and the pyogenic vibrio in the blood, and suggested using boric acid to kill these microorganisms before and after confinement . </P>

After the discovery of the germ theory of disease in the late nineteenth century european