Cholera and Interdisciplinary Science in 19th Century London

From: The Ghost Map: The Story of London's Most Terrifying Epidemic--and How It Changed Science, Cities, and the Modern World. Johnson, S. 2006.

Johnson describes the scavengers of London’s underclass in the 19th century, who performed the daily tasks of recyclers in the city. Numbering over one hundred thousand people, the scavengers recycled compost, metals, cloth and other materials. These forms of recycling have been found in all cities, and our current recycling system is a new less dangerous or labor intensive method. With the invention of water closets, water use increased and more excrement was flushed into cesspools, exacerbated by population increases. With this rise in excrement in the city, and the inability of recyclers to deal with it, came the rise of Cholera. Soho, a site of an earlier plague became an important location, both for Cholera outbreaks, and as a location for urban poets, artists, and writers like Marx, Blake, and Shelley. Much of the Soho area was located above a mass plague burial pit. John Snow became an important figure in medicine, and Soho was the grounds in which he examined the causal relationships between water and Cholera outbreaks.

John Snow was first focused on the use of ether for anesthetic. His method of bridging between different disciplines, from properties of gases, to dosage in humans and their effects on individuals, to the development of devices to control dosages. This unique type of thinking was more focused on chains and networks moving from scale to scale. Snow’s interest in Cholera, however, moved him from the individual to study of social groupings. While the contagionists argued for a Cholera contagion passed from person to person, and the miasmatists argued that Cholera lingered in unsanitary places, Snow argued that the disease was a contagion that is transferred through water, and not air, and provided evidence that showing that Cholera’s effects were related to shared water supplies. During an outbreak in Soho, both John Snow and Henry Whitehead began separate investigations. While Snow began to map out the cases of Cholera deaths in order to determine its location, Whitehead began to notice the class differentiation of cholera contraction, and the ability to fight off the disease. Additionally, Whitehead found that the water responsible for Cholera deaths ceased to cause people to contract the disease after a certain amount of time.

Edmund Cooper’s map successfully proved that the plague pit was not responsible for the cholera outbreak, but the map was too detailed to show that the culprit was actually the water pumps. Snow used voronoi diagrams to show the correspondence between Cholera cases, water pumps and footpaths. This map reflected an intimate street-level knowledge combined with a birds-eye view. Snow’s map provided further evidence for his waterborne theory, but his theory was not accepted until years later. Whitehead used this map in combination with an index of cases to further support the theory. Snow and Whitehead were using a new method for exploring urban space, and a model for managing and sharing information based on two principles; the importance of local experts and the lateral cross disciplinary flow of ideas.

Through the telling of the story of John Snow and Henry Whitehead, the author highlights the important and unique attributes of these people that allowed them to see beyond the dominant theories of the time, and make a breakthrough in the understanding of Cholera, disease, and urban environmental health. Scientists tend to think that our sophisticated techniques of analyzing spatial/temporal problems have developed with the increasing sophistication of our tools (i.e. satellites, laboratories, chemical assays, genetic analysis). The story of Snow and Whitehead demonstrates that unique flows of information between people, local knowledge, and the simple method of representing data on a hand-drawn map can lead to scientific breakthrough. While the tools we have at our disposal have vastly increased our capabilities, it is the ability to utilize multiple forms of knowledge, local context, and a fresh perspective with these tools that can lead to further breakthroughs.