Pas·teur \pȧs-tœr\ Louis (1822–1895), French chemist and bacteriologist. Pasteur made contributions that rank with the greatest in modern science. His achievements include pioneer work in modern stereochemistry that proved that racemic acid is a mixture of two optically different forms of tartaric acid; the investigation of problems encountered in the fermentation of wine and beer; and the demonstration that lactic, alcoholic, and other fermentations are caused by minute organisms. He also disproved the theory of spontaneous generation. He saved the French silk industry by discovering the bacilli that were the cause of two diseases of silkworms and developed the means of preventing the spread of these diseases. He discovered bacteria to be the cause of anthrax and developed in 1881 a method of inoculating animals with attenuated cultures of the bacteria causing fowl cholera. Finally, in 1885 he developed a preventive and curative treatment for rabies.