SOMETHING IN THE WATER
When cholera began to kill hundreds of London residents in the summer of 1854, one doctor put forth a very controversial theory: that a germ was responsible for the killer disease. Dr. John Snow, a London medical practitioner from an extremely modest background, felt that the still-controversial “germ theory” was the best one for explaining the outbreak. Of course, he faced a certain amount of ridicule—the tiny “animalcules” that had been observed under a microscope were certainly fascinating, but there was no hard evidence that they did anything to the human body.
The prevailing theory of the day was that disease was caused by bad air entering the lungs. The odor that supposedly caused illness went under two names at the time, the first being miasma. The second, more descriptive term came from the Italian phrase for bad air, mala aria, which translated into English as one word: malaria.
Despite the scorn of more learned scientists of his time, John Snow attained lasting fame as the person who could arguably be called the first formal epidemiologist in history. His achievements saved many lives and are all the more remarkable for the simplistic nature of the tools he had available to him at the time. Like a medical Sherlock Holmes, he investigated and identified the likely cause of the London cholera outbreak using nothing more than city maps, pencils, and string.