...us on both physics and chemistry. Becoming an assistant to one of his teachers, he began research that led to a significant discovery. He found that a beam of polarized light see Optics as rotated to either the right or the left as it passed through a pure solution of naturally produced organic nutrients, hereas hen such a beam as passed through a solution of artificially synthesized organic nutrients, no rotation took place. If, hoever, bacteria or other micro-organisms ere placed in the latter solution, after a hile it ould also rotate light to the right or left.Pasteur concluded that organic molecules can exist in one of to forms, called isomers that is, having the same structure and differing only in being mirror images of each other, hich he referred to as left-handed and right-handed forms. hen chemists synthesize an organic compound, these forms are produced in equal proportions, cancelling each others optical effects. Living systems, hoever, hich have a high degree of chemical specificity, can discriminate beteen the to forms, metabolizing one and leaving the other untouched and free to rotate light.ork on Fermentation After spending several years of research and teaching at Dijon and Strasbourg, Pasteur moved in 1854 to the University of Lille, here he as named Professor of Chemistry and dean of the faculty of sciences. This faculty had been set up partly to serve as a means of applying science to the practical problems of the industries of the region, especially the manufacture of alcoholic drinks. Pasteur immediately devoted himself to research on the process of fermentation. Although his belief that yeast plays some kind of role in this process as not original, he as able to demonstrate, from his earlier ork on chemical specificity, that the desired production of alcohol in fermentation is indeed due to yeast and that the undesired production of substances such as lactic acid or acetic acid that make ine sour is due to the presence of additional organisms, such as bacteria. The souring of ine and beer had been a major economic problem in France Pasteur contributed to solving the problem by shoing that bacteria can be eliminated by heating the initial sugar solutions to a high temperature.Pasteur extended these studies to such other problems as the souring of milk, and he proposed a similar solution heating the milk to a high temperature and pressure before bottling. This process is no called pasteurization.Disproof of Spontaneous Generation Fully aare of the presence of micro-organisms in nature, Pasteur undertook several experiments designed to address the question of here these germs came from. ere they spontaneously produced in substances themselves, or ere they introduced into substances from the environment Pasteur concluded that the latter as alays the case. His findings resulted in a fierce debate ith the French biologist Flix Pouchetand later ith the noted English bacteriologist Henry Bastionho maintained that under appropriate conditions instances of spontaneous generation could be found. These debates, hich lasted ell into the 1870s, although a commission of the Academy of Sciences officially accepted Pasteurs results in 1864, gave great impetus to improving experimental techniques in microbiology.Silkorm Studies In 1865 Pasteur as summoned from Paris, here he had become administrator and director of scientific studies at the cole Normale, to come to the aid of the silk industry in southern France. The countrys enormous production of silk had suddenly been curtailed because a disease of silkorms, knon as pbrine, had reached epidemic proportions. Suspecting that certain microscopic objects found in the diseased silkorms and in the moths and their eggs ere disease-producing organisms, Pasteur experimented ith controlled breeding and proved that pbrine as not only contagious but also hereditary. He concluded that only in diseased and living eggs as the cause of the disease maintained therefore, selection of disease-free eggs as the solution. By adopting this method of selection, the silk industry as saved from disaster.Germ Theory of Disease Pasteurs ork on fermentation and spontaneous generation had considerable implications for medicine, because he believed that the origin and development of disease are analogous to the origin and process of fermentation. That is, disease arises from germs attacking the body from outside, just as unanted micro-organisms invade milk and cause fermentation. This concept, called the germ theory of disease, as strongly debated by doctors and scientists around the orld. One of the main arguments against it as the contention that the role germs played during the course of disease as secondary and unimportant the notion that tiny organisms could kill vastly larger ones seemed ridiculous to many people. Pasteurs studies convinced him that he as right, hoever, and in the course of his career he extended the germ theory to explain the causes of many diseases.Anthrax Research Pasteur also determined the natural history of anthrax, a fatal disease of cattle. He proved that anthrax is caused by a particular bacillus and suggested that animals could be given anthrax in a mild form by vaccinating them ith attenuated eakened bacilli, thus providing immunity from potentially fatal attacks. In order to prove his theory, Pasteur began by inoculating 25 sheep a fe days later he inoculated these and 25 more sheep ith an especially strong inoculant, and he left 10 sheep untreated. He predicted that the second 25 sheep ould all perish and concluded the experiment dramatically by shoing, to a sceptical crod, the carcasses of the 25 sheep lying side by side.Rabies Vaccine Pasteur spent the rest of his life orking on the causes of various diseasesincluding septicaemia, cholera, diptheria, fol cholera, tuberculosis, and smallpoxand their prevention by means of vaccination. He is best knon for his investigations concerning the prevention of rabies, otherise knon in humans as hydrophobia. After experimenting ith the saliva of animals suffering from this disease, Pasteur concluded that the disease rests in the nerve centres of the body hen an extract from the spinal column of a rabid dog as injected into the bodies of healthy animals, symptoms of rabies ere produced. By studying the tissues of infected animals, particularly rabbits, Pasteur as able to develop an attenuated form of the virus that could be used for inoculation.In 1885 a young boy and his mother arrived at Pasteurs laboratory the boy had been bitten badly by a rabid dog, and Pasteur as urged to treat him ith his ne method. At the end of the treatment, hich lasted ten days, the boy as being inoculated ith the most potent rabies virus knon he recovered and remained healthy. Since that time, thousands of people have been saved from rabies by this treatment.Pasteurs research on rabies resulted, in 1888, in the founding of a special institute in Paris for the treatment of the disease...
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