The Ghost Map by Steven Johnson

Johnson, Steven. The Ghost Map: The Story of London’s Most Terrifying Epidemic—and How It Changed Science, Cities, and the Modern World. New York: Riverhead Books, 2006.

Steven Johnson presents the London cholera epidemic of 1854, and the work of Dr. John Snow and Rev. Henry Whitehead to link cholera to a water source, as multiple conflicts. It is a conflict between two species, Vibrio cholerae and Homo sapiens. It is a conflict of ideas between tradition and evidence. It is also a conflict between the problems arising from the high density living of cities and the human capacity to solve those problems.

In the first case, a colony of V. cholerae arguably won the bout in 1854. The outbreak was one of the most intense in London’s history, especially considering how rapidly it spread and killed. That it ended when it did may be due as much to happenstance and desperation to act as to a winning argument from evidence. In the immediate wake of the outbreak, the view that cholera was a waterborne illness was not widely accepted.

In the second case, the reasoned case from evidence eventually won over tradition. This led to a victory over cholera in London also. Though cholera is still a problem in parts of the world, the answers implemented in London (better sanitation and clean drinking water) will work anywhere.

Johnson is not too hard on the opponents of Snow. It was widely accepted that disease was caused by miasma, or bad air. It was hard for even intelligent people of the time to accept that disease could be caused by something that could not be detected by the senses (though an Italian scientist had viewed V. cholera under the microscope, it was not widely known). In fact, Snow hadn’t found the cause of cholera, only how it was transmitted.

In the last case, Johnson happily reports that human innovation has triumphed over the problems of cities so far. In many ways, cities are very advantages ways for people to live.

The last chapter launches from Snow’s study of the cholera epidemic, and the map he used to illustrate his findings, to how smarter maps and other innovations are creating a bright future for cities. Snow, Whitehead and science eventually are victorious in the aftermath of the 1854 epidemic, but it is cities that are the big winners.

Johnson brings up a number of vulnerabilities of cities in the next several decades. He is confident that the ingenuity show by the likes of Snow and Whitehead, and modern technology they couldn’t imagine, will overcome most of these problems. Even the problems that can’t be overcome don’t seem to be enough to end the urbanizing trend around the globe.

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