Dr John Snow’s map of the 1854 Broad Street Cholera Outbreak in Soho, London
Not many maps change the world. But Dr John Snow’s map of the 1854 cholera outbreak in Soho, London, which showed deaths clustered around a public water pump, changed our understanding of how the disease is transmitted, leading to changes in the design of water & waste infrastructure worldwide and huge improvements in public health.
We have two variants of his map in our catalogue. Click here for current stock availability. The editions of the maps that we stock were published by the River Pollution Commission in Hansard in 1874. In addition to his classic original untitled map, we also have a larger scale map which is a development of his original map, which highlights the then-recent changes to the local sewers, and believed locations of plague pits.
Snow’s map is regarded as a pioneering example of disease mapping. Dr Snow challenged the then-dominant theory that cholera and other diseases were caused by pollution or a noxious miasma or “bad air”. He observed that the deaths caused by cholera in the so called “Broad Street Cholera Outbreak” of 1854 (now Broadwick Street, Soho, London) were clustered around a single public water pump which he identified as the probable source of the outbreak. Using bars to represent the location of each cholera-related death, he used his “dot map” and statistics to illustrate the connection between the quality of the water provided by the water company, and cholera cases. His study was a major event in the history of public health, and is regarded as the founding event of the science of epidemiology. His findings resulted in a fundamental change to the design of the water and waste systems of London, and subsequently in other cities, which led to significant improvements in public health around the world.