An introduction describes cholera's first appearance in 1817 in India and its spread around the world, but Hempel begins her narrative proper in 1830, with reports from British diplomats about cholera in Russia and Germany. Preparations for its arrival in Britain involved a whole range of theories, both contagionist and anti-contagionist, and even more suggestions for treatment: "the inefficacy, or worse, of these remedies did not curb the medical profession's enthusiasm for them in the slightest". The first outbreak in Britain was in Sunderland, where commercial interests, wanting to avoid any kind of quarantine, forced the local doctors to change their statements.
Turning to John Snow, Hempel explores the life of a surgeon's apprentice, the problems obtaining bodies for dissection, and the often angry popular response to medical initiatives. She also covers Snow's training in London and his encounter with the politics of British medical organisations, and his personality and work on anaesthesia.
The response to the second major cholera outbreak in 1848 was led by a Board of Health dominated by Edwin Chadwick. A focus on "miasmatic" explanations, emphasizing environmental causes, was a medical mistake but did lead to advances in sanitation and more general public health, and brought attention to the horrors of child labour and orphanages.
In 1849 John Snow published a carefully argued pamphlet presenting his hypothesis, that cholera was transmitted by ingestion and spread through fecal matter, with the water supply implicated in mass outbreaks. This was ignored, despite a review in the Lancet: "unusually, no readers reached for their pens to support or denounce him. John Snow didn't even merit howls of derision. They simply ignored him." And attempts to find the agent of cholera using microscopes were bedevilled by as yet elementary procedures, not to mention by the idea that cholera was caused by a kind of fungus.
In 1854 Snow conceived the idea of a grand experiment to prove waterborne contagion, by comparing cholera cases in areas of South London that were served by different water companies. This was interrupted by the Broad St outbreak in Soho, which spread with shocking speed, killing 500 people in ten days, in a small area. The government conceived of a huge enquiry investigating all aspects of the disease, but this was again dominated by miasmatist ideas and was overly broad in scope, wandering as far afield as meteorology.
Meanwhile Snow immersed himself in Soho squalor, doing "shoe leather" mapping, tracing apparently anomalous cases back to the Broad St pump. This led to the famous incident where he convinced St James's Board of Guardians to remove the pump handle. Arthur Hassall found what he called vibriones in the discharges of cholera victims, but saw them as a consequence of cholera rather than a cause and failed to investigate further.
John Snow's publication in January 1855 should have settled the issue but was largely ignored. The government enquiry rejected or ignored Snow's work, persisting with miasmatist ideas, and Snow himself died in 1858. The curate Henry Whitehead tried to disprove Snow but was converted, and went on to find the origin of the Broad St outbreak, the "index" case.
Hempel finishes with an account of the fourth and last major cholera epidemic in Britain in 1866, the tracking down of contamination in water supplies, and the vindication of John Snow. She also covers Koch's identification of Vibrio cholerae and the actual workings of cholera, with a bit about its subsequent history.
Hempel tells a great story in The Strange Case of the Broad Street Pump, meshing together John Snow's life and the history of cholera in Britain. She digresses from these to provide illuminating background, on the state of public health and the medical system in mid-nineteenth century Britain, communications with the continent, the operation of London's water supplies, Semmelweis' work on puerperal fever in Vienna, and so forth. Anyone who enjoys popular science and history should find this a real treat.
Note: The Strange Case of the Broad Street Pump was published in the United Kingdom as The Medical Detective.