Louis Pasteur

Louis Pasteur was born on 27 December 1822 in Dole, Jura, France. He studied chemistry in Paris, earning his doctorate from the Ecole Normale Superieure, where he later taught. His early research focused on the optical properties of crystals and molecular asymmetry, work that contributed to the founding of stereochemistry.

In the 1850s, Pasteur investigated fermentation and demonstrated that it was caused by living microorganisms rather than being a purely chemical process. This research brought him into conflict with the prevailing spontaneous generation hypothesis, the idea that living organisms could arise from non-living matter. Through a series of carefully designed experiments using swan-necked flasks, he provided strong evidence against spontaneous generation and in favour of the idea that microbial contamination came from the environment.

Pasteur applied these findings to practical problems. He developed a process of using controlled heat to reduce microbial content in perishable liquids, a technique that became known as pasteurisation. He also investigated silkworm diseases that were damaging the French silk industry, identifying the causative organisms and proposing preventive measures.

From the 1870s onwards, Pasteur worked more directly on infectious disease. He studied chicken cholera, anthrax, and other conditions, developing attenuated preparations that could provide protection against disease. His work on rabies led to the development of a treatment administered after exposure to the virus, tested first in animals and later used in human cases beginning in 1885.

Pasteur founded the Institut Pasteur in Paris in 1887, which became a major centre for biomedical research. He died on 28 September 1895 in Saint-Cloud, near Paris, and was interred in the Institut Pasteur.