His medical discoveries provided direct support for the
germ theory of disease and its application in clinical medicine. He is best known to the general public for his invention of the technique of treating
milk and
wine to stop bacterial contamination, a process now called pasteurization. He is regarded as one of the three main founders of
bacteriology, together with
Ferdinand Cohn and
Robert Koch, and is popularly known as the "father of microbiology".
Pasteur also made significant discoveries in chemistry, most notably on the molecular basis for the
asymmetry of certain
crystals and racemization. He was the Director of the
Pasteur Institute, established in 1887, till his death, and his body lies beneath the institute in a vault covered in depictions of his accomplishments in
Byzantine mosaics.
Louis Pasteur was born on December 27, 1822, in
Dole, Jura,
France, into a
Catholic family of a poor
tanner. He was the third child of Jean-Joseph Pasteur and Jeanne-Etiennette Roqui. In 1827 the family moved to
Arbois, where Pasteur entered primary school in 1831. He was an average student in his early years, and not particularly academic, as his interests were
fishing and
sketching.
His pastels and portraits of his parents and friends, made when he was 15, were later kept in the museum of the Pasteur Institute in
Paris. In 1838 he left for Paris to join the Institution Barbet, but became homesick and returned home in November. In 1839 he entered the Collège Royal de Besançon and earned his
BA degree in 1840. He continued there for a
BSc degree with special mathematics but failed in 1841. He succeeded in 1842 from Dijon with a poor grade in chemistry.
After failing the entrance test for the
École Normale Supérieure in Paris in 1842, he succeeded in 1844, and received his medical license the next year. In 1846 he was appointed professor of physics at the Collège de Tournon at
Ardèche, but Professor
Antoine Jérome Balard wanted him back at the École Normale Supérieure as a graduate assistant (préparateur) for chemistry courses. He joined Balard and simutaneously started his research in
crystallography. In 1847 he submitted his two theses, one in chemistry and the other in physics.
After serving briefly as professor of physics at the Dijon
Lycée in 1848, he became professor of chemistry at the
University of Strasbourg, where he met and courted
Marie Laurent, daughter of the university's
rector, in 1849. They were married on May 29, 1849, and together had five children, only two of whom survived to adulthood; the other three died of
typhoid. These personal tragedies were his motivations for curing
infectious diseases.
Professional career
Pasteur was appointed to the Chair of chemistry in the Faculty of Sciences of the University of Strasbourg. In 1854, Pasteur was named Dean of the new Faculty of Sciences at
Lille University. It was on this occasion that Pasteur uttered his oft-quoted remark: "
dans les champs de l'observation, le hasard ne favorise que les esprits préparés" (In the field of observation, chance favors only the prepared mind.
In 1856, he moved to Paris as the director of scientific studies at the École Normale Supérieure. Pasteur took control of the 'École Normale' (1858–67) and began a series of reforms. The examinations became more rigid, which led to better results, greater competition, and increased prestige. He raised the standard of scientific work, leading to two serious student revolts.
In 1862 he was appointed professor of geology, physics, and chemistry at the
École nationale supérieure des Beaux-Arts, the position which held untill his resignation in 1867. He established the Pasteur Institute in Paris in 1887 in which he was its Director for the rest of his life.
