PASTEUR, LOUIS. — Born in Dôle on 27 December 1822, died at Villeneuve-l'Etang on 28 September 1895. He obtained his baccalaureate in letters (1840) at Besançon and in mathematics (1842) at Dijon. In 1843 he was appointed assistant in chemistry at the Ecole Normale, and in 1848 he was called as substitute professor to the chair of chemistry at the University of Strasbourg, where he subsequently became full professor (1852); in 1854 he was dean of the Faculty of Sciences at Lille. He was elected a member of the Académie de médecine (1873) and of the Académie française (1882); he was esteemed, admired, and honored by his contemporaries (Darwin, Bentham, Milne Edwards, Claude Bernard, etc.). He was a beautiful believing soul in an age of materialistic and positivistic science.
He began his research in crystallographic chemistry (1843), establishing the relationship between the crystalline form of bodies and their optical properties; these investigations led him to the study of the chemistry of fermentation (1848–1877), in which he established that every type of fermentation is the work of particular living microorganisms (ferments); in studying the origin of ferments, P. found himself confronted with the problem of spontaneous generation: through ingeniously devised and brilliantly conducted experiments, he demonstrated that microorganisms can originate only from microorganisms present in the environment; following the bitter controversy provoked by his experiments (especially by the interpretation given to them by Charlton Bastian, an English supporter of spontaneous generation), P. addressed the problem of the destruction of germs by heat, discovering the methods of sterilization and asepsis. At the request of the French government, he studied the disease of the silkworm (pébrine) and laid down rules for combating and preventing the scourge (1865). In the field of the etiology of infectious diseases, although preceded by Davaine and Koch, he won glory and popularity by discovering the pyogenic streptococcus (the agent of puerperal fever) in 1878 and indicating the means of preventing its infections; avian cholera (1875), swine erysipelas (1801), etc. Moreover, while studying anthrax (1877), he discovered that the inoculation of weakly virulent microbes into an animal organism causes a benign disease that protects it against the malignant form of the disease produced by virulent germs; by giving a rational basis to the principle of vaccination, already applied empirically by Jenner and others, P. made its generalization and dissemination possible; together with his collaborator Roux, he prepared vaccines against avian cholera, anthrax (1881), and rabies (1882).
In Paris he founded the « Institut P. », a famous laboratory where valuable research is being carried out in the field of biological sciences and serotherapy. P.'s works were all collected together (Oeuvres de P., Paris 1922).