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Bernard, Claude

experimental medicine paris talent

[bairnahr] (1813–78) French physiologist: pioneer of experimental medicine and physiological chemistry.

Bernard was the son of vineyard workers and he remained fond of country life; later he spent his time in either a Paris laboratory or, during the harvest, in the Beaujolais vineyards. His schooling was provided by his church, and at 19 he was apprenticed to an apothecary. His first talent was in writing for the theatre, but he was urged to qualify in a profession and chose medicine. He qualified for entry with some difficulty and emerged from his training in Paris as an average student. Then as assistant to he found his talent in experimental medicine. He never practised as a physician, and an early problem for him was how to make a living. He solved this by marrying a successful Paris physician’s daughter and living on the dowry until he succeeded to Magendie’s job in 1852. His marriage was unhappy.

Bernard’s discoveries were wide-ranging; many depended on his skill in vivisection, using mainly dogs and rabbits. In digestion he showed the presence of an enzyme in gastric juice; the nervous control of gastric secretion and its localization; the change of all carbohydrates into simple sugars before absorption; and the role of bile and pancreatic juice in the digestion of fats. He noted that the urine of herbivores is alkaline and that of carnivores acid, and he pursued the comparisons that these observations suggested. This led him to find that nutrition is complex and involves intermediate stages and synthesis as well as transport. He discovered glycogen, and sugar production by the liver. He studied the nervous system and discovered the vasomotor and vasoconstrictor nerves. Beginning with an attempt to prove simple ideas on animal combustion, Barnard showed that in fact the oxidation producing animal heat is indirect, and occurs in all tissues and not simply in the lungs. He studied the action of curare and other paralysing poisons and showed their use in experimental medicine. His approach to research was essentially modern; he combined experimental skill with theory and had a valuable talent for noting experimental results that were not in accord with existing ideas, which led to fruitful new concepts. Perhaps his greatest contribution to physiology was the idea that life is dependent on a constant internal environment (homeostasis); cells function best within a narrow range of osmotic pressure and temperature and bathed in a fairly constant concentration of chemical constituents such as sugars and metallic ions.

Bernard of Clairvaux, Saint [next] [back] Bernac (real name, Bertin), Pierre

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