Bernard, Claude (1813–1878)

French physiologist and founder of experimental medicine. Bernard first demonstrated that digestion is not restricted to the stomach, but takes place throughout the small intestine. He discovered the digestive input of the pancreas, several functions of the liver, and the vasomotor nerves which dilate and contract the blood vessels and thus regulate body temperature. This led him to the concept of the milieu intérieur (‘internal environment’) whose stability is essential to good health.

Bernard was born in St-Julien, Rhône-Alpes region, and studied medicine in Paris. He never practised but devoted himself to research. He was made professor 1854 at the Faculty of Sciences in Paris, and 1855 at the Collège de France.

Bernard performed a series of important experiments on the physiology of digestion, showing, for example, that pancreatic secretions were important in fat metabolism, and investigating the mechanisms of nervous control of gastric secretion. He also investigated the physiology of fetal tissues and the nutritive role of the placenta; and the role of drugs such as curare and opium alkaloids and their effects on the nervous system.

He summed up his work in The Introduction to the Study of Experimental Medicine 1865.