DSCI 490 Capstone Fall 2024

London, England had a big problem in the mid-1800s. Cholera (a disease that causes an infection in the small intestine) broke out and spread rapidly because of poor sanitation which led to drinking water sources being contaminated.

The Cholera outbreak from 1848-49 killed approximately 54,000-62,000 in London, and the outbreak from 1853-54 killed an estimated 31,000 in the city.

Physicians thought that Cholera was spread by the foul air permeating the City, the so-called “Miasma Theory.” 

A prominent London physician named Dr. John Snow a pioneer in the development and use of anesthetics also was keenly interested in the spread of disease, particularly Cholera.

Snow reasoned that if the Miasma Theory was true, then sewer workers and people who worked closer to the river would have a higher incidence of developing Cholera. Snow found that this wasn’t the case he reasoned that there was something else involved.

In 1854 he decided that he was going to get to the bottom of the problem. His first action was to interview patients sick with Cholera. Through the interviews, he discovered that they all got their water from the same local water pump. He then made a map of the area and began to plot the Chloria cases on the map. The map showed a concentration of Cholera cases around a water pump located at the corner of Broad Street and Cambridge Street.

To safeguard the population he visited the water pump and removed its handle so that people could not use the contaminated water. 

Further investigation determined that this pump was dug in too close proximity to a cesspit which was contaminated with the Cholera and which had been leaching contaminated material into the water well.

That map became known as “The Ghost Map”.

                               Ghost Map                                                                         Reproduction of the Pump