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PASTEUR, LOUIS (1822-1895)
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See also:PASTEUR, See also: On his deathbed he turned to the devoted pupils who watched over their master's last See also:hours. " OA en etes-See also:vous ? " he exclaimed. " Que faitesvous?" and ended by repeating his favourite words, " Il faut travailler."
The first incentive to his serious' study of chemistry was given by See also:hearing J. B. A. See also:Dumas lecture at the See also:Sorbonne; and ere long he broke new ground for himself, A. J. See also:Balard having given him an opportunity for chemical work by appointing him to the See also:post of laboratory assistant. A few words of explanation concerning Pasteur's first See also:research are necessary to give the See also: Perhaps the most remarkable See also:discovery of See also:modern chemistry is the existence of compounds, which, whilst possessing an identical See also:composition, are absolutely different bodies, judged of by their properties. The first of the numerous cases of See also:isomerism now known was noted, but unexplained, by J. J. See also:Berzelius. It was that of two tartaric acids, deposited from See also:wine-lees. The different behaviour of these two acids to a See also:ray of polarized See also:light was subsequently observed by J. B. See also:Biot. One possessed the power of turning the See also:plane of the polarized ray to the right; the other possessed no rotary power. Still no explanation of this singular fact was forth-coming, and it was reserved for the See also:young chemist from Franche-Comte to solve a problem which had baffled the greatest chemists and physicists of the See also:time. Pasteur proved that the inactivity of the one See also:acid depended upon the fact that it was composed of two isomeric constituents: one the See also:ordinary or dextrorotary acid, and the other a new acid, which possessed an equally powerful See also:left-handed See also:action. The See also:veteran Biot whose acquaintance Pasteur had made, was incredulous. He insisted on the repetition of the experiment in his presence; and when convinced of the truth of the explanation he exclaimed to the discoverer: " Mon See also:cher enfant, j'ai tant aime les sciences dans ma See also:vie que cela me fait battre le cceur." Thus at one step Pasteur gained a place of See also:honour among the chemists of the See also:day, and was immediately appointed See also:professor of chemistry at the Faculte of See also:Science at Strasburg, where he soon afterwards married Mlle See also:Laurent, who proved herself to be a true and See also:noble helpmeet. Next he sought to prepare the inactive See also:form of the acid by artificial means; and after See also:great and long-continued labour he succeeded, and was led to the commencement of his classical researches on See also:fermentation, by the observation that when the inactive acid was placed in contact with a See also:special form of See also:mould (Penicillium glaucum) the right-handed acid alone was destroyed, the left-handed variety remained unchanged. So well was his position as a leading See also:man of science now established that in 1854 he was appointed professor of chemistry and See also:dean of the Faculte See also:des Sciences at See also:Lille. In his inaugural address he used significant words, the truth of which was soon manifested in his See also:case: " In the See also: " The chemical See also:act of fermentation," writes Pasteur, " is essentially a correlative phenomenon of a vital act beginning and ending with it." But we may ask, as Pasteur did, Why does beer or milk become sour on exposure to ordinary air? Are these invisible germs which cause fermentation always See also:present in the See also:atmosphere? or are they not generated from the organic, but the non-organized constituents of the fermentable liquid? In other words, are these organisms not spontaneously generated? The controversy on this question was waged with spirit on both sides; but in the end Pasteur came off victorious, and in a series of the most delicate and most intricate experimental researches he proved that when the atmospheric germs are absolutely excluded no changes take place. In the interior of the See also:grape, in the healthy See also:blood, no such germs exist; crush the grape, See also:wound the flesh, and expose them to the ordinary air, then changes, either fermentative or putrefactive, run their course. But place the crushed See also:fruit or the wounded See also:animal under conditions which preclude the presence or destroy the life of the germ, and again no change takes place; the grape juice remains sweet and the wound clean. The application of these facts to surgical operations, in the able hands of See also:Lord See also:Lister, was productive of the most beneficent results, and has indeed revolutionized surgical practice. Pasteur was now the acknowledged See also:head of the greatest chemical See also:movement of the time, the recipient of honours both from his own See also:country and abroad, and installed at the Ecole normale in Paris in a dignified and important post. Not, how-ever, was it without See also:grave opposition from powerful See also:friends in the See also:Academy that Pasteur carried on his work. Biot—who loved and admired him as a son—publicly announced that his enterprise was chimerical and the problem insoluble; Dumas evidently thought so too, for he advised Pasteur not to spend more of his time on such a subject. Yet he persevered: " Travailler, travailler toujours " was his See also:motto, and his See also:patience was rewarded by results which have not merely rendered his name immortal, but have benefited humanity in a way and to a degree for which no one could have ventured to See also:hope. To begin with a comparatively small, though not unimportant, See also:matter, Pasteur's discoveries on fermentation inaugurated a new era in the See also:brewing and wine-making See also:industries. See also:Empiricism, hitherto the only See also:guide, if indeed a guide at all, was replaced by exact scientific knowledge; the connexion of each phenomenon with a controllable cause was established, and See also:rule-of-thumb and quackery banished for ever by the See also:free See also:gift to the See also:world of the results of his researches. But his See also:powers of patient research and of See also:quick and exact observation were about to be put to a severe test. An epidemic of- a fatal See also:character had ruined the French See also:silk producers. Dumas, a native of the See also:Alais See also:district, where the disease was rampant, urged Pasteur to undertake its investigation. Up to that time he had never seen a silkworm, and hesitated to See also:attempt so difficult a task; but at the reiterated See also:request of his friend he consented, and in See also:June 1865 went to the See also:south of See also:France for the purpose of studying the disease on the spot. In See also:September of the same See also:year he was able to announce results which pointed to the means of securing See also:immunity from the dreaded See also:plague. The See also:history of this research, of the See also:gradual elimination of the unimportant conditions, of the recognition of those which controlled the disease, is one of the most fascinating chapters of scientific discovery. Suffice it here to say that careful experiment and accurate observation succeeded in ascertaining the cause of the disease and in preventing its recurrence, thus bringing back to prosperity the silk See also:trade of France, with all that this entails. " There is no greater See also:charm," says Pasteur, " for the investigator than to make new discoveries; but his See also:pleasure is heightened when he See also:sees that they have a See also:direct application to See also:practical life." Pasteur had the See also:good See also:fortune, and just See also:reward, of seeing the results of his work applied to the benefit both of the human See also:race and of the animal world. It is to him that the world is indebted for the introduction of methods which have already worked wonders, and bid See also:fair to render possible the preventive treatment of all infectious diseases. Just as each See also:kind of fermentation possesses a definite organized ferment, so many diseases are dependent on the presence of a distinct microbe; and just as the gardener can pick out and grow a given plant or See also:vegetable, so the bacteriologist can (in most cases) eliminate the See also:adventitious and grow the special organism—in other words, can obtain a pure cultivation which has the power of bringing about the special disease. But by a See also:process of successive and continued artificial cultures under different conditions, the See also:virus of the organism is found to become attenuated; and when this weakened virus is administered, the animal is rendered immune against further attacks. The first disease investigated by Pasteur was that of chicken See also:cholera, an epidemic which destroyed to % of the French fowls; after the application of the preventive method the See also:death-See also:rate was reduced to below 1%. Next came the successful attempt to See also:deal with the fatal See also:cattle See also:scourge known as See also:anthrax. This is also caused by the presence of a microbe, of which the virus can also be attenuated, and by inoculation of this weakened virus the animal rendered immune. Many millions of See also:sheep and oxen all over the world have thus been treated, and the rate of mortality reduced from to to less than 1%. As to the See also:money value of these discoveries, T. H. See also:Huxley gave it as his See also:opinion that it was sufficient to See also:cover the whole cost of the See also:war See also:indemnity paid by France to See also:Germany in 1870. The most interesting of Fasteur's investigations in preventive and curative See also:medicine remains to be told. It is no less than a cure for the dread disease of See also:hydrophobia in man and of rabies in animals; and the See also:interest of the achievement is not only that he successfully combated one of the most mysterious and most See also:fell diseases to which man is subject, but also that this was accomplished in spite of the fact that the special microbe causing the disease had not been isolated. To begin with, Pasteur, in studying the malady in See also:dogs, came to the conclusion that the virus had its seat in the See also:nerve centres, and he proved that the injection of a portion of the matter of the See also:spinal See also:column of a rabid See also:dog into the See also:body of a healthy one produces in the latter with certainty the symptoms of rabies. The next step was to endeavour so to modify and weaken the virus as to enable it to be used as a preventive or as an antitoxin. This, after long and serious labour, he effected; the dog thus inoculated proved to be immune when bitten by a rabid animal. But this was not enough. Would the inoculation of the attenuated virus have a remedial effect on an animal already bitten ? If so, it might be possible to See also:save the lives of persons bitten by mad dogs. Here again experiment was successful. A number of dogs were inoculated, the same number were untreated, and both sets were bitten by rabid animals. All the treated dogs lived; all the untreated died from rabies. It was, however, one thing to experiment on dogs, and quite another to do so on human beings. Nevertheless Pasteur was bold enough to try. The trial was successful, and by doing so he earned the gratitude of the human race. Then, on the 14th of See also:November 1888, the Institut Pasteur was founded. Thousands of See also:people suffering from bites from rabid animals, from all lands, have been treated in this See also:institute, and the death-rate from this most horrible of alldiseases has been reduced to less than 1%. Not only in Paris, but in many cities throughout the world, institutes on the See also:model of the See also:original one have been set up and are doing beneficent work, all arising from the See also:genius and labour of one man. At the inauguration of the institute Pasteur closed his oration with the following words: " Two opposing laws seem to me now in contest. The one, a See also:law of blood and death, opening out each day new modes of destruction, forces nations to be always ready for the See also:battle. The other, a law of See also:peace, work and health, whose only aim is to deliver man from the calamities which beset him. The one seeks violent conquests, the other the See also:relief of mankind. The one places a single life above all victories, the other sacrifices hundreds of thousands of lives to the ambition of a single individual: The law of which we are the See also:instruments strives even through the carnage to cure the wounds due to the law of war. Treatment by our antiseptic methods may preserve the lives of thousands of soldiers. Which of these two laws will prevail, Geri only knows. But of this we may be sure, that science, in obeying the law of humanity, will always labour to enlarge the frontiers of life." See also:Rich in years and in honours, but See also:simple-minded and affectionate as a See also:child, this great benefactor to his See also:species passed quietly away near St See also:Cloud on the 28th of September 1895. Mention need only be made of Pasteur's chief See also:works, as follows: Etudes sur le vin (1866), Etudes sur le vinaigre (1868), Etudes sur la maladie des vers d soie (1870), Etudes sur la biere (1876). He began the practice of inoculation for hydrophobia in 1885. See Vie de Pasteur, by Rene Vallerey-Radot (Paris, igoo). (H. E. R.). Additional information and CommentsThere are no comments yet for this article.
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