John Snow (1813-1858)
Dr. Snow, 1857 by anonymous.
John Snow was born on 15 March 1813 in York. He started his medical career in 1836, got an apothecary and surgeon's license at age 25 from Hunterian School of Medicine and and finally received a doctor of medicine degree in 1844. He lived in Soho, where he also established a medical practice. He is seen as a pioneer of the germ theory and the founding father of epidemiology.
John Snow first encountered cholera in 1831 and began researching on it. He was convinced that diseases such as cholera are spread through contact with contaminated water - in contrast to the prevailing view that it was transmitted by stench. He wrote down his idea of waterborne illnesses in his book On the Mode of Communication of Cholera.
INFOBOXMiasma Theory
(Μίασμα, miasma, ancient Greek: "pollution") The term describes the belief that bad air is the cause of illness and disease. The idea goes back to ancient Greece but the term was first used in the 17th or 18th century. The theory was very appealing to people at that time since it explained the epidemics in the fetid and almost undrained areas in the cities. |
To prove his hypothesis, John Snow did research in two experiments in different areas.
In 1854 cholera occurred mainly among people living along the Thames. During the outbreak in Soho his survey showed that the majority of victims (61 persons of 83) drank contaminated water from Broad Street Pump. These were numbers the Board of Governors of St. James' Parish could not ignore and thus closed the water pump on 8 September 1854.
For his second experiment the doctor visited many households to determine which company supplied them with water. There were the Vauxhall and Southwark Water Company, which drew their water from the polluted Thames and the Lambeth Water Company, that had moved its supply north beyond the city's outpouring of sewage.
Snow found out that people supplied by the Vauxhall and Southwark Water Company were 9 times more likely to get cholera than those supplied by Lambeth Water Company:
Vauxhall and Southwark Company: 315 deaths per 10,000 houses
Lambeth Water Company: 37 per 10,000 houses
Snow marked the distribution of cases of cholera in The Ghost Map.
In 1854 cholera occurred mainly among people living along the Thames. During the outbreak in Soho his survey showed that the majority of victims (61 persons of 83) drank contaminated water from Broad Street Pump. These were numbers the Board of Governors of St. James' Parish could not ignore and thus closed the water pump on 8 September 1854.
For his second experiment the doctor visited many households to determine which company supplied them with water. There were the Vauxhall and Southwark Water Company, which drew their water from the polluted Thames and the Lambeth Water Company, that had moved its supply north beyond the city's outpouring of sewage.
Snow found out that people supplied by the Vauxhall and Southwark Water Company were 9 times more likely to get cholera than those supplied by Lambeth Water Company:
Vauxhall and Southwark Company: 315 deaths per 10,000 houses
Lambeth Water Company: 37 per 10,000 houses
Snow marked the distribution of cases of cholera in The Ghost Map.
However, Snow was not fully able to prove how cholera exactly spread, so many doctors remained sceptical. They argued that many who presumably drank dirty water did not contract the disease. People were also drinking bad water before the epidemics, so it could not be the cause. It finally took 30 years for the "waterborne theory" to be accepted.