Chevreul, Michel Eug�ne 1786-1889
French chemist and gerontologist

Born in Angers, Anjou province, he studied chemistry at the Coll�ge de France in Paris and at Harvard. Most of his working life was spent at the Museum of Natural History in Paris. For some years he was director of the dyeworks at the Gobelins Tapestry factory. He investigated the physics and psychology of colour. De la loi du contraste simultan� (1839, 'Of the Law of Simultaneous Contrast'), which influenced many of the Impressionists, argued that our perception of the intensity and hue of any colour is conditioned by the degree of contrast with neighbouring colours. Chevreul was also a pioneer of organic analysis. His studies of the saponification process demonstrated that soaps are combinations of a fatty acid with an inorganic base, a discovery which opened up vast industries. He noticed the phenomenon of isomerism, reported that diabetic urine contains glucose and studied the psychiatric effects of old age.