Staff Pick - The Ghost Map by Steven Johnson

[Brian Bess]

A journal of the cholera week

Most of us are aware of how filthy London in the nineteenth century was. We have seen filmed depictions of Dickens novels even if we haven’t read the novels themselves that describe crowded, unsanitary conditions of people living elbow to elbow right next to the densely polluted Thames River. I was not aware, though not surprised, that there was a powerful and rapidly accelerating cholera epidemic stemming from the Broad Street area of central London in September of 1854.

From our 21st century perspective it seems obvious that drinking polluted water is a guaranteed method of spreading disease. However, in mid-nineteenth century England, large numbers of intelligent, scientific men and women sincerely believed that such disease had miasmic origin i.e. foul-smelling odors could spread germs that were deadly when inhaled. Apparently their sense of smell was more highly developed than their sense of taste. It is hard for me to imagine that anyone could drink water contaminated by sewage without detecting something severely unhealthy. I must recall that this was in a pre-sanitation era, where matters as clean drinking water were rarely addressed.

The primary holder of the theory in London of 1854 was a hard-working epidemiologist named John Snow. His experiments with ether and chloroform as reliable methods of anesthesia informed him enough to reject a miasmic theory of disease generation. If foul odors were the cause of such disease, then how could one explain sixty-year old ‘night-soil men,’ those people with the most unenviable jobs of cleaning the ‘night-soil,’ the human excrement, from the cesspools of the neighborhood, collecting it and carting it off to farmers outside the city walls?

Snow conducted exhaustive experiments on the water from the various pumps in the area and his conclusive evidence and argument was persuasive enough to prompt the authorities to remove the handle from the Broad Street pump. Determining where people actually acquired their water and deposited their waste was much more difficult. He enlisted the aid of the local curate Henry Whitehead, who had originally rejected Snow’s theory of the contaminated water, became a convert, and relied on his knowledge of the population of the area to pinpoint the actual ‘index case’—a sick baby’s soiled diapers were deposited in the Broad Street well.

The partnership of Snow and Whitehead solved the mystery of the origin of the cholera and tipped the scales in persuading the health authorities to evaluate the purity of the drinking water, leading to a massive drainage and sewage disposal system that radically improved the health of the London inhabitants and served as an example for other large cities to follow.

Johnson deftly conveys scientific issues relating to bacteria and germ analysis in terms that are easy for the lay reader to understand. His narrative style draws the reader into a real-life whodunit thriller where the real killer is proven to be a microbial murderer and the detectives are the unlikely pairing of an anesthesiologist and a minister. It is a fairly taut and fast-paced account where the padding that fills out the length is almost as interesting as the account of the 1854 cholera epidemic itself. Johnson describes the evolution of toilets, the development of London’s sewer system, the importance of population density for a disease that travels in human excrement, the positive and negative aspects of urbanization and the development of cartographic maps, high tech versions of Snow’s ‘ghost map’ where he pinpointed the location of all the deaths in central London in relation to the Broad Street pump, in which conclusions can be derived from analysis of statistical and demographic data. Modern day Snows and Whiteheads have more sophisticated tools for rooting out disease. They will need all the sophistication and accuracy they can acquire because they have their work cut out for them in a world where the globalization of the planet has produced stakes that are even higher than cholera in central London.