Cannon, Walter B(radford) (1871–1945)

US physiologist. He devised the use of radiopaque chemicals for X-ray diagnosis of the gastrointestinal system in 1897. In the 1930s, he began his pioneering work on chemical neurotransmission; his ‘sympathins 1 and 2’ are now known as epinephrine and norepinephrine.

Cannon was born in Prairie du Chien, Wisconsin. He was a medical student at Harvard 1896–1900, and joined Harvard's faculty 1900–42. He investigated the physiology of digestion until 1911. Inquiries into the physiological effect of emotions 1911–17, including studies of surgical trauma during World War I, led him to postulate that the adrenals' action on the sympathetic nervous system is responsible for an animal's ‘fight or flight’ response. He coined the term ‘homeostasis’ in 1926 to describe an organism's tendency to maintain physiological stability. He expounded this concept in his book, The Wisdom of the Body (1932). A visiting professor at numerous institutions and a member of many international societies, he was an antitotalitarian activist who believed that a scientist should also be a world citizen.