Louis Pasteur was a French chemist and microbiologist whose research helped establish the role of microorganisms in fermentation and disease. Born in Dole in 1822, he trained in chemistry and physics and held academic posts at Strasbourg, Lille and Paris. His early studies of molecular asymmetry were followed by experiments showing that particular microorganisms cause specific forms of fermentation and spoilage.

Pasteur challenged theories of spontaneous generation and provided important experimental support for germ theory. He developed heat-treatment methods for reducing microbial contamination in wine and other liquids, a process later known as pasteurisation. His work on infectious diseases led to vaccines against conditions including anthrax and rabies, although some of his experimental methods and claims were later reassessed by historians. In 1887, the Pasteur Institute was founded in Paris for research and treatment of infectious disease. Pasteur died near Paris in 1895.