Famous French chemist who made many notable discoveries in chemistry, biology and medicine.
In 1848, Pasteur separated tartaric acid into two forms, both having the same chemical formula; however, one form rotated a polarized light beam to the right (dextro-rotatory) and the other to the left (levo-rotatory). Pasteur’s discovery of molecular dyssymmetry opened up the held of stereo-chemistry. In 1856, Pasteur showed that fermentation is caused by yeast, not by chemical agents; some years later, he showed that similar micro-organisms were responsible for causing wine to go sour and beer to deteriorate. In 1862, Pasteur stirred up opposition by ridiculing the theory of spontaneous generation that living organisms can arise from inanimate matter. In 1877, Pasteur noted that some bacteria produce substances that kill other bacteria, the basis of antibiotics that made possible the use of antibodies in the 20th century. In 1885, he uncovered the mechanism for immunization through vaccination. Pasteur put forward the germ theory of disease in 1880.