The Ghost Map by Steven Johnson

I like epidemiology. Is that weird? I always read the articles about diseases like ebola and malaria when they appear on the New York Times science page, or in The Atlantic. I also like history, especially British history. Thus this book, about the London cholera epidemic of 1854 intrigued me. It tells the story of a doctor, John Snow, who proved that cholera spreads via contaminated water rather than through miasma (“bad air”), which was the prevailing wisdom of the time. He arrived at this theory through careful observation and statistical analysis, and managed to convince the city authorities to remove the handle from a pump in Soho, thereby ending the outbreak and proving his point. His map of the area, which showed the numbers of dead and their connection to the contaminated Broad Street pump was a groundbreaking feat of scientific analysis and communication.

Johnson tells the story of the cholera epidemic well. He manages to make it suspenseful, even though we already know how it ends. He also paints a vivid portrait of mid-Victorian London, a crowded, dirty city where the poor were concentrated in squalid slums like those in Soho where the outbreak occurred.

But wait, there’s more! The book also provides a history of modern epidemiology, and of the waste disposal industry. Without sewers, we’d all still be getting cholera, he says. Indeed Johnson hails the London sewer system (whose construction he describes in loving detail) as one of the engineering marvels of the modern world, far superior (in his eyes) to other feats of the same era, such as the Eiffel Tower, for example.

And Johnson keeps on going! In the last chapter of the book he tries to draw comparisons between the cholera epidemic of the mid-19^th century and threats to modern urban life, such as bioterrorism and rogue nuclear strikes. Ack. I really didn’t want to hear about those. His point is that we can address modern threats through the same methods that Snow used on cholera: by paying attention to science instead of superstition, and by being open to new ideas, even if they go against the popular wisdom. I guess so. But really, I was mostly interested in how Snow came up with that idea about the pump handle.

Wikepedia has a good article about Snow and the cholera outbreak. It also has a short article about the London sewerage system.

(Book 45, 2007)