London was hit by a major cholera epidemic in 1832. At first Londoners thought that the deadly disease, which originated in India in 1817, was spread by "bad air", the miasma theory. However, in 1849, Dr. John Snow declared that cholera was a water borne disease, revolutionary thinking at the time. The city government wasn't prepared to accept his findings and continued to function as before. London was ripe for another epidemic.
The disease struck for the second time in 1854. This time Dr. John Snow had a ringside seat to observe the disease and record his findings. The city was the perfect breeding ground for disease: two and a half million people lived in a 30 mile circumference. The ever increasing problem remained: What to do with the waste that all of these Londoners produced? Many cellars had cesspools under their floorboards where human feces and urine were dumped. However, these cesspools were overflowing. Rather than finding a proper outlet for the waste, the British government, looking for a quick fix, ruled to dump the extra waste in the River Thames, London's water source.
"On August 28, 1854, working class Londoner Sarah Lewis tossed a bucket of soiled water into a cesspool of her squalid apartment building and triggered the deadliest outbreak of cholera in the city's history." One hundred and twenty seven people died in the next three days. By September 10, the death toll soared to 500.
Dr. John Snow was ready with paper and pencil to observe the cholera outbreak and record his findings. He sketched out a map of London, highlighting the areas most affected by the disease. He came to the conclusion that the source of the outbreak was the Broad Street pump. Interestingly enough, his theory rang true when it was discovered that employees at the Broad Street Brewery, who drank beer rather than the water at this time, did not succumb to cholera. The fermentation process would kill any bacteria in the beer. Although the Broad Street pump handle was later removed, Dr. Snow's theory was not readily embraced. It was easier for the British government to sweep the problem under the rug, at least for the time being.
Cholera is the best of all sanitary reformers, wrote The Times in 1848. Ten years later, the comment was proven correct when pedestrians walking over the London Bridge covered their noses with handkerchiefs to ward off the foul odour emanating from the River Thames. Parliament's curtains had to be soaked in lime. Still, dignitaries sitting in Parliament could stand the stench no longer and proposed legislation to fix the problem.
Enter Joseph Bazalgette, the engineer who would design London's sewer system. Author Steven Johnson likens Bazalgette's sewers to the Eiffel Tower or the Brooklyn Bridge -- a massive project which made its mark on the city. The first section of the system opened in 1865, but it was too late for London's East End, which did not yet have sewers.
In 1866, the last cholera epidemic hit the city. The disease inspired investigations into living conditions in London, particularly the slums. Evangelist Thomas Barnardo, training to be a medical doctor in a London hospital, and intending on working as a missionary in China, was moved by the suffering he saw in the East End and decided to stay. Dr. Barnardo would go on to open a series of homes for destitute children, one of Britain's great social reformers.
Dr. Snow's ghost map of cholera would be considered the founding event of the discipline of epidemiology.
Note: For more information, read The Ghost Map: The Story of London's Most Terrifying Epidemic by Steven Johnson.