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596 General History of Europe 1083. Struggle against Disease-Producing Bacteria. At first sight it would seem hopeless to attempt to avoid bacteria, since they are so minute and so numerous, but experience has shown that they can be fended off in surgical cases by a scrupulous sterilization of everything that enters into the operation. That typhoid fever is due ordinarily to impure water or milk, that tuberculosis is spread mainly through the dried sputum of those afflicted with it, that the germs of yellow fever and ma- laria are transmitted by the mosquito, all suggest obvious means of precaution which will greatly reduce the chances of spreading the diseases. Moreover, remedies are being discovered in addition to these preventive measures. Pasteur found that animals could be rendered immune to hydrophobia by injections of the virus of the disease. So-called antitoxins (counter poisons) have been discovered for diphtheria, lockjaw, and typhoid fever, but none has yet been found for tuberculosis or pneumonia. Much remains to be discovered in regard to susceptibility to disease. 1084. Importance of the History of Science. It may well be that men of science, not kings or warriors or even statesmen, are to be the heroes of the future. Perhaps during the twentieth cen- tury the progress of science and its practical applications will be recognized as the most vital element in the history of the eight- eenth and nineteenth centuries. Our histories will have to be re- written. Diderot's Encyclopedia will receive more space than the wars of Frederick the Great, and the names of Lyell, Darwin, Lister, Koch, and Pasteur will take their places beside those of Metternich, Cavour, and Bismarck. Louis PASTEUR