Louis Pasteur

Louis Pasteur ForMemRS (/ˈluːi pæˈstɜːr/, French: [lwi pastœʁ] ^ⓘ; 27 December 1822 – 28 September 1895) was a French chemist, pharmacist, and microbiologist renowned for his discoveries of the principles of vaccination, microbial fermentation, and pasteurization, the last of which was named after him. His research in chemistry led to remarkable breakthroughs in the understanding of the causes and preventions of diseases, which laid down the foundations of hygiene, public health and much of modern medicine. Pasteur's works are credited with saving millions of lives through the developments of vaccines for rabies and anthrax. He is regarded as one of the founders of modern bacteriology and has been honored as the "father of bacteriology" and the "father of microbiology" (together with Robert Koch; the latter epithet also attributed to Antonie van Leeuwenhoek).

Pasteur was responsible for disproving the doctrine of spontaneous generation. Under the auspices of the French Academy of Sciences, his experiment demonstrated that in sterilized and sealed flasks, nothing ever developed; conversely, in sterilized but open flasks, microorganisms could grow. For this experiment, the academy awarded him the Alhumbert Prize carrying 2,500 francs in 1862.

Pasteur is also regarded as one of the fathers of the germ theory of diseases, which was a minor medical concept at the time. His many experiments showed that diseases could be prevented by killing or stopping germs, thereby directly supporting the germ theory 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. Pasteur also 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 sodium ammonium tartrate initiated the field of optical isomerism. This work had a profound effect on structural chemistry, with eventual implications for many areas including medicinal chemistry.

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.

Louis Pasteur was born on 27 December 1822, in Dole, Jura, France, to a Catholic family of a poor tanner. 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. Pasteur entered primary school in 1831. He was dyslexic and dysgraphic.^{[dubious – discuss]}

He was an average student in his early years, and not particularly academic, as his interests were fishing and sketching. He drew many pastels and portraits of his parents, friends and neighbors. Pasteur attended secondary school at the Collège d'Arbois. In October 1838, he left for Paris to enroll in a boarding school, but became homesick and returned in November.

In 1839, he entered the Collège Royal [fr] at Besançon to study philosophy and earned his Bachelor of Letters degree in 1840. He was appointed a tutor at the Besançon college while continuing a degree science course with special mathematics. He failed his first examination in 1841. He managed to pass the baccalauréat scientifique (general science) degree from Dijon, where he earned his Bachelor of Science in Mathematics degree (Bachelier ès Sciences Mathématiques) in 1842, but with a mediocre grade in chemistry.

Later in 1842, Pasteur took the entrance test for the École Normale Supérieure. During the test, he had to fight fatigue and only felt comfortable with physics and mathematics. He passed the first set of tests, but because his ranking was low, Pasteur decided not to continue and try again next year. He went back to the Parisian boarding school to prepare for the test. He also attended classes at the Lycée Saint-Louis and lectures of Jean-Baptiste Dumas at the Sorbonne. In 1843, he passed the test with a high ranking and entered the École Normale Supérieure. Later, he was a student of Jean-Baptiste Boussingault at the Conservatoire national des arts et métiers. In 1845 he received the licencié ès sciences  [fr] degree. In 1846, he was appointed professor of physics at the Collège de Tournon [fr] in Ardèche. But the chemist Antoine Jérôme Balard wanted him back at the École Normale Supérieure as a graduate laboratory assistant (agrégé préparateur). 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: (a) Chemistry Thesis: "Recherches sur la capacité de saturation de l'acide arsénieux. Etudes des arsénites de potasse, de soude et d'ammoniaque."; (b) Physics Thesis: "1. Études des phénomènes relatifs à la polarisation rotatoire des liquides. 2. Application de la polarisation rotatoire des liquides à la solution de diverses questions de chimie."