The Ghost Map: The Story of London's Most Terrifying Epidemic--and How It Changed Science, Cities, and the Modern World

by Steven Johnson

The courage of those who stayed to fight the disease—or investigate its origins—is all the more impressive in this light, since simply breathing in the vicinity of an outbreak was assumed by almost everyone to be risking death. John Snow had at least the courage of his convictions to rely on: if the cholera was in the water, then venturing into the Golden Square neighborhood at the height of the epidemic posed no grave threat, as long as he refrained from drinking the pump water during his visits. The Reverend Whitehead had no such theory to allay his fears as he spent hour after hour sitting in the presence of the sick, and yet not once in his writing about the Broad Street outbreak is there mention of his own private dread.