ISOMERISM.) In the autumn of 1848 Pasteur moved to Dijon as professor of physics, but in the beginning of the following year was transferred as professor of chemistry to Strasbourg, where he soon married Mlle. Laurent, who proved herself a devoted and noble helpmeet. While at Strasbourg he was awarded the ribbon of the Legion of Honour for having artificially produced from the ordinary com mercial acid that racemic acid which up to then had only once been produced, and that by accident. Pasteur's appointment in 1854 as professor and dean of the new Faculte des sciences at , Lille placed him in a district where his interest in fermentation could be applied to the manufacture of alcohol from grain and beet-sugar, and his energies were now bent towards discovering the causes of the diseases of beer and wine. On examining the yeasts of sound and unsound beer under the microscope, he at once saw that the globules of the sound beer were nearly spherical, whilst those of the sour beer were elongated. He continued his researches, and, of ter his removal in 1857 to the Ecole normale as director of scientific studies, definitely proclaimed that fermen tation is the result of minute organisms, and that when a fermenta tion failed, either the necessary organism was absent or unable to grow properly. Hitherto all explanations of the phenomenon of fermentation had been obscure and without experimental founda tion, but Pasteur supported his contention by showing that milk could be soured by injecting a number of the organisms from but termilk or beer kept unchanged if similar organisms were excluded. "The chemical act of fermentation," wrote Pasteur, "is essentially a correlative phenomenon of a vital act beginning and ending with it." (See FERMENTATION.) The recognition of the fact that both lactic and alcohol fermen tations were hastened by exposure to air naturally led Pasteur to wonder whether his invisible organisms were always present in the atmosphere or whether they were spontaneously generated. By a series of intricate experiments, including the filtration of air and the famous exposure of unfermented liquids to the pure air of the high Alps, he was able to declare with certainty in 1864 that the minute organisms causing fermentation were not spon taneously generated, but came from similar organisms with which ordinary air was impregnated. Pasteur was now acknowledged the leading chemist of his day and the recipient of honours both from his own country and abroad. Lord Lister, who saw the ap plicability of these discoveries to surgery, was able to revolutionize surgical practice by utilizing in 1865 carbolic acid to exclude the atmospheric germs and thus prevent putrefaction in compound fractures.
In June 1865, after much persuasion from his old teacher, J. B. Dumas, Pasteur went to the south of France to investigate the disease of silkworms which was ruining the French silk indus try. (See SILK.) Three years later he was able to announce that he had isolated the bacilli of two distinct diseases and that he had found a method of preventing contagion as well as of detecting diseased stock. These results not only saved the prosperity of the French silk industry but that of all silk-producing countries. In the October of 1868 Pasteur was struck with semi-paraly sis, but he was able to return to Paris and continue his experi ments on fermentation. The war of 1870 made him more desirous than ever of devoting himself to the perfecting of French brewing. In 1872 he wrote his famous paper on fermentation, and in 1873 he became a member of the French Academy of Medicine. In 1874 he received a life-pension from the National Assembly. Three years later Pasteur, who had already revolutionized the production of alcohols, established the germ theory and saved the silk industry, turned his attention to the fatal cattle scourge known as anthrax, and within two years had demonstrated the entire natural history of the disease. In 188o, however, his researches were diverted to chicken cholera, an epidemic which destroyed o% of the French f owls. He was soon able to isolate the germ of this disease, and by cultivating an attentuated form of the germ and inoculating fowls with the culture, he proved that they were rendered immune from virulent attacks of cholera. He now returned to his researches on anthrax, a disease upon which Davaine and Koch had been working. Following the same methods that he had used in cholera, he isolated the bacillus, and by cultivating it in oxygen at a temperature of 42°C produced a successful inoculation mate rial which, by inducing a mild attack of anthrax, rendered the inoculated animal immune for a time against a culture of full strength. These methods Pasteur called vaccination, because of his desire to render homage to Jenner, who had discovered means for protecting man against smallpox by inoculating with cowpox. (See ANTHRAX and VACCINATION.) As to the money values of these discoveries, which had brought Pasteur world fame, T. H. Huxley expressed the opinion that it was sufficient to cover the whole cost of the war indemnity paid by France to Germany in 1870. He himself chose to remain poor and to set an example of simplicity.