(The London of John Snow displays the handle of Pump at Broad Street that he dismantled.)
John Snow ( March 15 1813) is considered to be the father of modern epidemiology for the statistical mapping methods he initiated
In the early Nineteenth century, physicians in Europe were convinced that cholera was caused by bad-smelling air. This was known as the MIASMA theory.
The theory held that the origin of epidemics like Typhoid, Cholera, Malaria was due to a miasma, emanating from rotting organic matter. (Malaria means Mal air.)
Accordingly in Paris, people tried to collect clean air from the top of Eiffel tower and release it at ground level to prevent the spread of cholera.
In London, the authorities decided that the number of cholera cases could be reduced if they could improve London’s air. It was decided that the city’s sewage which was till then disposed in open spaces will be dumped into the River Thames. But the Thames also happened to be the source of the city’s drinking water.
As a result, London suffered the worst cholera epidemic in 1850s.
On one such outbreak on 31 August 1854, 616 people died alone in Soho, London. The London Board of Health investigated the out break and attributed the 1854 epidemic to MIASMA.
John Snow, the physician however couldn’t agree. He used a dot map to plot all the cases of Soho and was astounded to find that all the cases of cholera were tied up to one single hand pump at the crossing of Broad Street and Cambridge street.
But there was a big exception.The workers of the nearby Broad street Brewery which also drew water from the same pump didn’t have a single attack. This gave Dr Snow his second clue. He found out that in the process of brewing, the water of the brewery used to be boiled several times before consumption.
The germ theory of Pasteur or the Koch’s postulate were yet to come out. Audaciously, John Snow inferred that this boiling killed the cholera bacteria present in the pump water.
The then medical establishment of London refused to buckle, however. They stood by their miasma theory, and even declared that Snow lived in a sewer.
To prove his theory, Dr Snow himself dismantled the handle of the pump. Magically, Soho became cholera free. Later on, it was found that this particular pump was drawing water from a nearby cess pit which used to receive the washings of a family suffering from cholera.
This logically established the fecal-oral route of cholera transmission. By boiling drinking water, and improved sanitation the regular cholera epidemic of London could be controlled.
In memory, the John Snow Society holds “Pumphandle Lectures” every year on subjects of public health.
Dr Ramakanta's Ideas 