Our next book is the story of a horrible Cholera outbreak in London, England in the late summer of 1854, The Ghost Map: The Story of London’s Most Terrifying Epidemic–and How It Changed Science, Cities, and the Modern World by Steven Johnson. It tells the story of a deadly outbreak of cholera in the late summer of 1854, and how careful gathering of information and analysis of the data led to an understanding of its mode of transmission and effective public health measures to prevent it. The result was the creation of the science of epidemiology.
The book focuses on two men. Dr. John Snow, who help found the Epidemiological Society of London 4 years previously, and was a pioneer in anesthesiology. Snow lived about 5 blocks from the epicenter of the epidemic. Rev. Henry Whitehead was the 28 year old assistant curate of the local C of E church. They both spent every available minute, independently, visiting the victims and gathering information about their circumstances, until the epidemic had run its course. Later, they were both appointed by the local health board to a committee to investigate the epidemic. Initially, they supported rival theories of the spread of cholera, but Whitehead was a nascent skeptic and eventually came to support Snow’s evidence and reasoning, which fit perfectly with his own disproving of the conventional theories of the day, principally the miasma theory of disease.
Both Snow and Whitehead showed great courage and concern for the victims during the outbreak, although we now know they were actually in little real danger. Whitehead did drink some of the water, which many people thought was actually a cure for cholera, and drank in large quantities. Most likely by that time, the cholera in the well had all died since the well contained little of the plankton cholera normally thrives on in the wild, but no one knew that at the time. (The germ theory of disease lay about a decade in the future.)
Snow had been gathering evidence to support his hypothesis that cholera was waterborne to explain earlier outbreaks when the 1854 Soho epidemic occurred. Snow’s map of the location of victims and his investigations, especially of the outlying cases, convinced him his theory was correct. The local council wasn’t convinced, rightly pointing out that it didn’t account for people who drank the suspect water but didn’t get sick. However, in a spirit of caution, they had the handle removed from the pump of the suspect Broad Street well, which while probably too late to stop the current outbreak, did prevent a second outbreak when the father of the first victim, patient zero, became one of the last people to die and almost certainly recontaminated the well. (The cesspool in the cellar of his house was only a few feet from the well.)
Whitehead had been gathering evidence to disprove all the various versions of the conventional miasma theory, and rightly pointed out some logical gaps in Snow’s theory. Together, Snow and Whitehead gathered the needed data and, much to Whitehead’s surprise, made further maps that showed beyond any doubt that cholera was waterborne and the Broad Street well was the culprit. For example, they measured the actual walking distance between the homes or workplaces of the victims and all the nearby public wells, and showed that in almost every case, the Broad Street well was the closest. They also showed the distribution of the cases did not support other hypotheses, such as that the air near the ground or the social class of the victims or the newly built sewer system or the recently disturbed pit containing the remains of many of the 100,000 victims of the London Plague of 1665.
The Kindle version of the book only contains one of the maps, in a very small, almost unreadable format. I don’t know if the print version is better. Anyway, a much bigger version of his original map is here.
Steven Johnson has written 8 books on the history of science, technology and innovation.
We will be meeting at our usual time and location, at 3:00 PM in Harvard’s Northwest Science Building, 52 Oxford Street, Cambridge, on Saturday, June 22. Remember to bring your appetite and, if you wish, a snack, preferably one made with boiled water. Also optional, you can RSVP on our Facebook event page.
As always, Mary will be leading the discussion of the book the next day (June 23) at tbe Skepchick Book Club.