The Man Who Made Paris Afraid of Its Own Hands

Nineteenth-century Paris had many things to fear: revolutions, the cholera, the Prussians, the price of bread, and Baron Haussmann arriving with a measuring tape and a demolition crew. By the end of the century it had acquired a new one, invisible and everywhere. For this, Parisians could thank a short, stubborn chemist from the Jura Mountains who did not shake hands and did not, as a rule, apologise. Louis Pasteur died on 28 September 1895. October seems a fitting month to look at the man who taught the city that the most dangerous thing in the room was usually too small to see. A Tanner’s Son Among the Crystals Pasteur was born in 1822 in Dole, the son of a tanner and Napoleonic veteran. As a student he was, by his teachers’ accounts, diligent rather than dazzling. He was rated “mediocre” in chemistry at one examination, which should comfort anyone whose report card has ever been a disappointment. He came to Paris to study at the École Normale Supérieure on the rue d’Ulm, and the…