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 was responsible for disproving the doctrine of spontaneous generation. He performed experiments that showed that without contamination, microorganisms could not develop. Under the auspices of the French Academy of Sciences, he demonstrated that in sterilized and sealed flasks nothing ever developed, and in sterilized but open flasks microorganisms could grow.[7] Although Pasteur was not the first to propose the germ theory, his experiments indicated its correctness and convinced most of Europe that it was true.
Today, he is often regarded as one of the fathers of germ theory.[8] Pasteur made significant discoveries in chemistry, most notably on the molecular basis for the asymmetry of certain crystals and racemization. Early in his career, his investigation of tartaric acid resulted in the first resolution of what is now called optical isomers. His work led the way to the current understanding of a fundamental principle in the structure of organic compounds.
He was the director of the Pasteur Institute, established in 1887, until his death, and his body was interred in a vault beneath the institute. Although Pasteur made groundbreaking experiments, his reputation became associated with various controversies. Historical reassessment of his notebook revealed that he practiced deception to overcome his rivals.
Education and early life
Louis Pasteur was born on December 27, 1822, in Dole, Jura, France, to a Catholic family of a poor tanner.[4] He was the third child of Jean-Joseph Pasteur and Jeanne-Etiennette Roqui. The family moved to Marnoz in 1826 and then to Arbois in 1827.[11][12] 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.[4] He drew many pastels and portraits of his parents, friends and neighbors.[14] Pasteur attended secondary school at the Collège d'Arbois.[15] In October 1838, he left for Paris to join the Pension Barbet, but became homesick and returned in November.[16]
In 1839, he entered the Collège Royal at Besançon to study philosophy and earned his Bachelor of Letters degree in 1840.[17] He was appointed a tutor at the Besançon college while continuing a degree science course with special mathematics.[18] He failed his first examination in 1841. He managed to pass the baccalauréat scientifique (general science) degree in 1842 from Dijon but with a mediocre grade in chemistry.[19]
Later in 1842, Pasteur took the entrance test for the École Normale Supérieure.[20] He passed the first set of tests, but because his ranking was low, Pasteur decided not to continue and try again next year.[21] He went back to the Pension Barbet to prepare for the test. He also attended classes at the Lycée Saint-Louis and lectures of Jean-Baptiste Dumas at the Sorbonne.[22] In 1843, he passed the test with a high ranking and entered the École Normale Supérieure.[23] In 1845 he received the licencié ès sciences (Master of Science) degree.[24] In 1846, he was appointed professor of physics at the Collège de Tournon (now called Lycée Gabriel-Faure [fr]) in Ardèche, but the chemist Antoine Jérôme Balard wanted him back at the École Normale Supérieure as a graduate laboratory assistant (agrégé préparateur).[25] He joined Balard and simultaneously started his research in crystallography and in 1847, he submitted his two theses, one in chemistry and the other in physics.