Snow had assembled convincing evidence supporting contagion theory, and he believed that the 1854 epidemic could further strengthen his case. At the time, there were two dominant theories for how cholera spread-the contagion theory (that some kind of agent passed between cholera victims) and the miasma theory (that bad odors, emanating from certain environments, caused cholera, especially in people who had certain “internal constitutions”). Snow had already made a name for himself as a pioneering anesthesiologist however, he’d become interested in cholera epidemics after an outbreak of the disease in 1848. Whitehead knew almost all the families living in the neighborhood, and he traveled from house to house, speaking to the families of cholera victims.Īnother important figure in the 1854 epidemic was a young doctor named John Snow. However, in communities without access to clean water, such as Victorian London, cholera posed a major threat.ĭuring the 1854 epidemic, there was a priest named Henry Whitehead living near Soho. The simplest cure for cholera is a combination of clean water and electrolytes. When it infects a human being, cholera targets the small intestine, causing dehydration, vomiting, and diarrhea. Cholera is a bacterial, waterborne disease that has existed for thousands of years, although it’s only become a major killer in the modern, urban era (in ancient times, most communities weren’t dense enough to facilitate the spread of the disease).

Within a few days, dozens of people had become seriously ill. Soon afterwards, there was a cholera epidemic in the London neighborhood of Soho.

In 1854, a child became violently ill the mother, Sarah Lewis, threw the baby’s soiled diapers in a cesspool in the basement of her home. The sewers were often clogged with waste, and “night-soil men” made good money cleaning up excrement at night and dumping it at the edges of the city. At a time when the majority of the world lived in rural communities, in London millions of people lived within a few miles of each other-and the city lacked a sanitation system that could deal with millions of people’s garbage and waste. In the 1850s, London was the largest city in Europe, and one of the filthiest cities in the world.

Ghost Map by Steven Johnson