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

by Steven Johnson

MIASMA CERTAINLY HAD THE FORCE OF TRADITION ON ITS side. The word itself is a derivation from the Greek term for pollution; the notion of disease being transmitted by poisoned air dates back to Greek medicine of the third century B.C. Hippocrates was so obsessed with air-quality issues that his medical tracts sometimes sound like instructions for a novice meteorologist. His treatise On Air, Water, and Places begins: “Whoever wishes to investigate medicine properly, should proceed thus: in the first place to consider the seasons of the year, and what effects each of them produces for they are not at all alike, but differ much from themselves in regard to their changes. Then the winds, the hot and the cold, especially such as are common to all countries, and then such as are peculiar to each locality.” (Farr would echo this philosophy centuries later: his Weekly Returns would invariably include a brief weather report, before getting to the body count.) Just about every epidemic disease on record has been, at one point or another, attributed to poisoned miasma. The word “malaria” itself derives from the Italian mal aria, or “bad air.”