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Pasteur, Louis

vaccine major disease success

[paster] (1822–95) French chemist and microbiologist: founder of stereochemistry and developer of microbiology and immunology; exponent of germ theory of disease.
Pasteur is one of the greatest figures in science, who made major changes in all the fields in which he worked. He was enormously talented, with great powers of scientific intuition; he was also ambitious, arrogant, combative and nationalistic.

His father served in the Peninsular War and then returned to the family tanning business in Dôle, near the Swiss border. Louis was the only son; there were three daughters. His school record was only moderate, but just good enough for him to go to Paris and to hope for entry at the teacher training college, the École Normale. In preparing for this for a second time (the first time his physics was classed as ‘passable’ and chemistry ‘mediocre’), he went to lectures on chemistry by , along with 700 other students. The subject captured him, he became a ‘late developer’, and all his future work showed a chemical approach even to biological problems.

His first major research, done at the École Normale, concerned tartaric acid (a by-product in wine making). Had shown that one form of the acid is optically active (ie it rotates polarized light when in solution). Pasteur examined a salt of the optically inactive form of tartaric acid and showed that the crystals were of two kinds, which were non-superposable mirror-images of each other (ie were dissymmetric). He separated these and showed they were both active, with equal and opposite rotation. He deduced, correctly, that the molecules themselves must therefore be dissymmetric, a fundamental idea and one that was more fully explored by . It was the beginning of stereochemistry.

  This work had interested Pasteur in fermentation, and when he became professor of chemistry at Lille in 1854 he found this useful, because alcohol-making was Lille’s main industry. Back at the École Normale from 1857 he continued this interest, which was to carry him from chemistry to biology and from there to medicine. In becoming a microbiologist and improving wine- and beer-making technology in his early middle-age, Pasteur became convinced that spontaneous generation did not occur. Work should have established the view expressed : ‘all cells come from cells’. But the experimentation is not easy and the debate continued. However, Pasteur’s now-classic studies showed in the early 1860s that putrefaction of broth and fermentation of sugar did not occur spontaneously in sterile conditions, but could be readily initiated by airborne microorganisms. He put his view with typical force, and it has been generally accepted since. He introduced pasteurization (brief, moderate, heating) to kill pathogens in wine, milk and other foods. Since fermentation, putrefaction and suppuration of wounds were fairly widely regarded as kindred processes, it was reasonable for to use Pasteur’s principles to revolutionize surgery, but Pasteur himself was not involved in this. However, in 1860 he said he planned to work in medicine, and he eventually achieved his own revolution there.

His first experience with animal diseases was with silkworms, then a major French industry but much threatened by infections. Pasteur, helped by a microscope and his fermentation experience and with wife, daughter and several assistants acting with him as novice silk-growers, fairly soon established procedures to deal with the two infections then rife. Then, in 1868 when he was 46, he had a stroke; he was fully paralysed for 2 months and partly paralysed thereafter. His work habits were unchanged, but his irritability increased. Most experiments now had to be performed under his direction but not with his own hands. In one way this suited him; he disliked vivisection, but saw it as essential for some of his research, and preferred others to perform the work.

Only in the late 1870s did Pasteur achieve success against a disease in a larger animal. In 1879 by a fortunate chance he noted that if a chicken-cholera bacillus culture was ‘aged’ or ‘attenuated’ by storage, it failed to produce the disease in chickens on injection; but the injected chickens (after an interval) were resistant even to infection by a fresh culture. He deduced that the change in virulence of the culture on attenuation, so that it protected but did not infect, could be compared with the use of the mild cowpox vaccine against the virulent smallpox, studied before 1800. Pasteur used the idea to make a vaccine against anthrax (a major disease of cattle, and sometimes found in man). The scheme worked well, and Pasteur staged a demonstration for agriculturists in May 1881 on a farm. A herd of 50 sheep, cows and goats was divided into two equal groups, and one group of 25 was inoculated with ‘attenuated’ vaccine. After 2 weeks all 50 were given an injection of a strong anthrax culture. Two days later, a crowd formed to see the dramatic result: the protected 25 were all healthy; of the others, 22 were dead, two dying, one sickening.

In 1880 he began to study rabies. The work was dangerous, and difficult because the first step he wished to take–isolation of the pathogen–was not then possible; it is now known to be a virus. However, he could inject dogs, guinea pigs and rabbits with rabid saliva and thereby infect them; and he found that spinal cord from a rabid rabbit, if kept in dry air for a few days, formed an attenuated vaccine which could be used to protect and to treat other animals. However, he was understandably fearful of human trials. Then in 1885 he was brought 9-year-old Joseph Meister, who had been bitten 14 times by a rabid dog. The child was treated with the vaccine, survived and later became a care-taker at Pasteur’s institute. In 1886 2671 patients were treated, and only 25 died. This success made Pasteur world-famous, and an Institute was built for his research, by public subscription; it was opened in 1888. But by then he was old and ill, and rabies was his last success. Pasteur’s notebooks were not opened to the public until 1971. It then emerged that some of his trials were very inadequate and some claims improved on the record; for example, the vaccine used on Meister appears to have been tested on only a few dogs and not on 50 as Pasteur later claimed.

Medicine was never the same after his work; infectious disease could now be combated by established techniques and research guided by a general theory. Vaccines were sought against most major diseases, but only in some cases could a vaccine be made. Pasteur had all the marks of genius, including an intuition on when to continue with a study of details until success followed and when to leave a field for other workers to explore. He had a number of distinguished co-workers; the best was his wife. He was buried in the chapel of the Pasteur Institute in Paris. In 1940 the invading Nazis ordered Meister to open the ornate crypt for inspection, but the gatekeeper chose to kill himself rather than do so.

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