Louis Pasteur

Early life and education: Louis Pasteur was born to a modest family in Dole, Jura; his father was a tanner and a Napoleonic veteran. Pasteur studied at the Royal College of Besançon and later at the École Normale Supérieure in Paris, earning a doctorate in 1847 after early work in crystallography and stereochemistry that demonstrated molecular chirality (optical isomerism). Scientific breakthroughs and fermentation work: In the 1850s–1860s Pasteur investigated fermentation and spoilage in wine and beer industries, showing that specific microorganisms were responsible for particular fermentation processes and that heating could prevent spoilage—this gave rise to pasteurization and strengthened the microbial (germ) theory of disease. His work resolved important industrial problems and won government and commercial attention. Vaccination and immunology: From the 1870s onward Pasteur moved into disease and immunity research. He produced attenuated strains to create vaccines: first for chicken cholera, then for anthrax in farm animals, and ultimately for rabies in humans—his rabies vaccine was famously used to treat a young boy bitten by a rabid dog in 1885, demonstrating practical medical application. Later life, institutional legacy and death: Pasteur suffered a serious stroke in 1868 but continued research and public engagement; he founded the Pasteur Institute (opened in 1888) to continue research and applied medicine. He was awarded national honors, received a state funeral at his death on 28 September 1895, and his remains were later interred at the Pasteur Institute.