Mapping Cholera, 19th century
Medical Topography: Mapping Cholera in the Nineteenth Century by Lauren Killingsworth
John Snow’s map of the Broad Street 1854 cholera outbreak is a common reference point for historians of cartography. Snow is often recognized as the father of epidemiology and is praised for his use of cartography to demonstrate a causal correlation between contaminated water and cholera fatalities. Snow, however, was not the first to use a thematic map of disease fatalities and environmental factors to investigate the cause of disease. In 1798, the physician Valentine Seaman mapped yellow fever fatalities and unsanitary sites side-by-side on a plan of New York City, the earliest known example of medical cartography. When cholera reached Europe in the 1830s, the field then known as “medical topography” burgeoned. The explosive, sudden outbreaks of cholera and the high mortality of the disease led to widespread panic. Miasmatic theory dominated popular opinion; most people believed that disease rose from putrid, foul-smelling matters in the air. Determining the cause of the “cholera morbus” became a chief priority.
The threat of cholera, coupled with the rising popularity of statistics and scientific mapping, led academics to turn to cartography. City plans depicting cholera fatalities and potential sources of disease became increasingly popular. The growing output of disease maps was largely fueled by the debate between two camps of academics: the contagionists (those who believed cholera could be spread between people) and the localists (or non-contagionists, those who believed that disease was incited by local, foul matters rather than infected people). Disease maps provided an ideal medium for physicians to advocate their theories.
This case examines medical cartography from 1832 to 1865, highlighting the diverse approaches used to better understand the origin of cholera and to promote specific theories. The original approach involved plotting disease fatalities (often alongside proposed sources of disease) on a city plan. Within this style, there was great variety in the data selected for display, symbols used, and use of statistics. Maps were cleverly designed to support either the contagionist or localist theory. Some mapmakers departed from the classical approach, creating innovative infographics, world maps tracing the progress of disease, and sanitary maps highlighting sewage systems. These diverse cholera maps provide important insight into the role of cartography in advancing medical science and shaping popular perceptions of disease in the nineteenth century.