Born Dec. 27, 1822, in Dôle, Jura; died Sept. 28, 1895, in Villeneuve l’Etang, near Paris. French microbiologist, chemist, and founder of modern microbiology and immunology. Member of the Académie des Sciences (1862) and the Académie de Médecine (1853) and one of the “Immortals” of the Académie Française (1881). Corresponding member (1884) and honorary member (1893) of the St. Petersburg Academy of Sciences.

Pasteur graduated from the École Normale Supérieure in 1847. He was a professor at the University of Strasbourg from 1849, the University of Lille from 1854, the École Normale from 1857, and the University of Paris from 1867. He participated in the Revolution of 1848 as a member of the National Guard.

Beginning in 1888, Pasteur served as the first director of the Pasteur Institute, a microbiology research institution founded with funds from international public subscription. The Russian scientists E. Metchnikoff, S. N. Vinogradskii, N. F. Gamaleia, V. M. Khavkin, A. M. Bezredka, and others worked fruitfully at the institute along with other foreign scientists.

Pasteur’s research was characterized by a close relationship between theory and practice. His earliest work, which dealt with the optical asymmetry of molecules, formed the basis of stereochemistry. Pasteur showed that differences in the optical activity of tartaric acid crystals (levorotary and dextrorotary) are determined by the presence of two asymmetric molecular forms. He demonstrated the possibility of separating optical isomers by means of microorganisms that selectively consume one of the isomers.

Starting in 1857, Pasteur studied processes of fermentation, including lactic, alcoholic, and acetic fermentation and butyric fermentation, which he discovered. Contrary to the prevailing “chemical” theory of the German chemist J. von Liebig, Pasteur showed that fermentation is caused by the activity of various microorganisms. He also discovered the phenomenon of anaerobiosis—the capacity for life in the absence of molecular oxygen—and the existence of obligate anaerobic bacteria. He showed that fermentation is the source of energy for the microorganisms that cause it.

Pasteur’s work provided a scientific foundation for wine-making, beer brewing, and other branches of the food industry. He suggested a method for preventing wine from spoiling (pasteurization) that was later used in the processing of other beverages, such as beer, milk, and fruit juices. His experiments demonstrated conclusively that spontaneous generation of life does not occur under modern conditions.

In 1870, Pasteur completed a study of pébrine, established the disease’s contagious nature, detected the time of its maximum proliferation, and recommended control measures. He investigated many other contagious diseases of animals and man, including anthrax, puerperal fever, rabies, fowl cholera, and swine erysipelas, and conclusively demonstrated that they are caused by specific microorganisms. Based on his conception of artificial immunity, he proposed the method of inoculation and demonstrated its effectiveness by vaccinating sheep against anthrax in 1881. Pasteur and P. P. E. Roux began investigating rabies in 1880 and carried out the first vaccination against this disease in 1885.