Pasteur died from complications of a series of strokes, having spent his final years partially paralyzed but still directing research at the institute in Paris that bore his name. His work proving that microorganisms cause disease and fermentation, and his development of vaccines for rabies and anthrax, laid the foundation for modern microbiology, food safety, and immunology, saving uncountable lives in the century after his death.
Pasteur's breakthroughs read almost like a checklist of modern medicine's origin story: he disproved spontaneous generation with elegant swan-neck flask experiments, developed pasteurization to kill pathogens in wine and milk, and created vaccines against anthrax in livestock and rabies in humans. His 1885 treatment of a boy bitten by a rabid dog, using a vaccine he had not yet tested on a human, is often cited as one of medicine's great calculated risks - the boy survived, and Pasteur became an international hero.
By the time of his death, Pasteur had suffered several strokes that left him partially paralyzed and dependent on his family. He reportedly spent his last conscious hours listening to his wife and grandchildren read to him. The Pasteur Institute he founded in 1887 continues his work today, and his name is attached to everyday words like pasteurized milk, a quiet but permanent monument to a chemist who insisted, against considerable skepticism, that invisible creatures were killing people.
Key people: Louis Pasteur