A Matter of Life and Death

John Snow successfully petitioned to have the handle at the Broad Street pump removed, thereby removing access to the water from that well. The data here shows beyond a shadow of a doubt that his conclusions were correct: people in Soho were getting cholera from the Broad Street water pump.

Moreover, using this data and knocking on doors and doing countless interviews, Dr. Snow was able to determine the source of the cholera: A young mother named Sally Lewis used the pump to clean her baby’s diaper, then threw the dirty diaper into the cesspool of the Broad Street pump. The cholera germs therefore entered the water system and killed hundreds.

Other doctors and scientists of the day refused to believe Dr. Snow’s theory that cholera could be spread by water. They held firm to the belief that cholera was spread through miasma, or dirty air. A priest named Reverend Henry Whitehead decided to conduct his own interviews of people who had been stricken with cholera so that he could prove Dr. Snow wrong. After many, many interviews, his data revealed the same conclusions: the source of the cholera was the dirty diaper that contaminated the drinking water.

As more and more people began to accept Dr. Snow’s conclusions, the city of London came to a stark realization: disease could be caused by dirty living conditions. Eventually they realized that to save lives, they would need to provide clean water and help clean up neighborhoods like Soho. Of course, by that time, thousands of people had already died.

Dr. Snow did not live long after his important work investigating cholera. In his research on anesthesia, he frequently tested new techniques on himself, not wanting to put others in danger. All this testing impacted his kidneys and renal system, which eventually caused a stroke that was severe enough to kill him.

Nevertheless, Dr. Snow used science and data to prove where cholera came from, thereby saving countless lives. He is considered the “Father of Epidemiology.” Epidemiologists who study outbreaks of diseases use many of the same techniques today, such as collecting data, mapping out the location of people with the disease, and interviewing people and families of those struck by the disease. Because of Dr. Snow’s work, we are better able to track down contagious diseases and stop them before they impact too many people.