Walter Bradford Cannon

Overview
Walter Bradford Cannon (October 19, 1871 – October 19, 1945) was an American physiologist, Professor and chairman of the Department of Physiology at Harvard Medical School, who developed the concept of homeostasis, and popularized it in his book The Wisdom of the Body, published in 1932 by W. W. Norton, New York.

Biography
Walter Cannon was born in Prairie du Chien, Wisconsin in 1871. In his autobiography The Way of an Investigator, Cannon counts himself among the descendents of Jacques de Noyon. His Calvinist family was intellectually active, including readings from James Martineau, John Fiske (philosopher), and James Freeman Clarke. Cannon's curiosity also lead him to Thomas Henry Huxley, John Tyndall, George Henry Lewes, and William Kingdon Clifford. A high school teacher, Mary Jeannette Newson, became his mentor. "Miss May" Newson motivated and helped him take his academic skills to Harvard University. Attracted to the biological sciences as an undergraduate, Cannon began working in Bowditch's laboratory as a first-year student at Harvard Medical School in 1896. In 1900 he received his medical degree.

Cannon kept working in Harvard as an instructor in the Department of Physiology in 1900. From 1906 until 1942 he was Higginson Professor and chairman of the of the Department of Physiology at Harvard Medical School.

He was President of the American Physiological Society from 1914 to 1916.

He was married to Cornelia James Cannon, a best-selling author. The couple had five children. One son was Dr. Bradford Cannon, a military plastic surgeon and radiation researcher. The daughters are Wilma Cannon Fairbank, Linda Cannon Burgess, Helen Cannon Bond and Marian Cannon Schlesinger, a painter and author living in Cambridge, Massachusetts. Walter Cannon died in 1945 in Lincoln, Massachusetts.

Work
Walter Cannon began his career in science as a Harvard undergraduate in the year 1896. Henry Pickering Bowditch, who had worked with Claude Bernard, directed the laboratory in physiology at Harvard. Here Cannon began his research: he used the newly discovered X rays to study the mechanism of swallowing and the motility of the stomach. He demonstrated deglutition in a goose at the APS meeting in December 1896 and published his first paper on this research in the first issue of the American Journal of Physiology in January 1898.

In 1945 Cannon summarized his career in physiology by describing his focus at different ages:
 * Age 26 - 40: digestion and the bismuth meal
 * Age 40 - 46: bodily effects of emotional excitement
 * Age 46 - 51: wound shock investigations
 * Age 51 - 59: stable states of the organism
 * Age 59 - 68: chemical mediation of nerve impulses (collaboration with Arturo Rosenblueth)
 * Age 68 + : chemical sensitivity of nerve-isolated organs

Scientific contributions

 * Use of salts of heavy metals in X-Rays
 * He was one of the first researchers to mix salts of heavy metals (including bismuth subnitrate, bismuth oxychloride, and barium sulfate) into foodstuffs in order to improve the contrast of X-ray images of the digestive tract. The barium meal is a modern derivative of this research.


 * Fight or flight
 * In 1915, he coined the term fight or flight to describe an animal's response to threats (Bodily Changes in Pain, Hunger, Fear and Rage: An Account of Recent Researches into the Function of Emotional Excitement, Appleton, New York, 1915).


 * Homeostasis
 * He developed the concept of homeostasis from the earlier idea of Claude Bernard of milieu interieur, and popularized it in his book The Wisdom of the Body,1932. Cannon presented four tentative propositions to describe the general features of homeostasis:
 * Constancy in an open system, such as our bodies represent, requires mechanisms that act to maintain this constancy. Cannon based this proposition on insights into the ways by which steady states such as glucose concentrations, body temperature and acid-base balance were regulated.
 * Steady-state conditions require that any tendency toward change automatically meets with factors that resist change. An increase in blood sugar results in thirst as the body attempts to dilute the concentration of sugar in the extracellular fluid.
 * The regulating system that determines the homeostatic state consists of a number of cooperating mechanisms acting simultaneously or successively. Blood sugar is regulated by insulin, glucagons, and other hormones that control its release from the liver or its uptake by the tissues.
 * Homeostasis does not occur by chance, but is the result of organized self-government.


 * Cannon-Bard theory
 * Cannon developed the Cannon-Bard theory with physiologist Philip Bard to try to explain why people feel emotions first and then act upon them.


 * Dry mouth
 * He put forward the Dry Mouth Hypothesis, stating that people get thirsty because their mouth gets dry. He did an experiment on two dogs. He cut their throats and inserted a small tube. Any water swallowed would go through their mouths and out by the tube, never reaching the stomach. He found out that these dogs would lap up the same amount of water as control dogs

Publication
Cannon wrote several books and articles.
 * 1910, A Laboratory Course in Physiology
 * 1911, The Mechanical Factors of Digestion
 * 1915, Bodily Changes in Pain, Hunger, Fear and Rage
 * 1923, Traumatic Shock
 * 1932, The Wisdom of the Body
 * 1936, Digestion and Health
 * 1937, Autonomic Neuro-effector Systems, with Arturo Rosenblueth
 * 1945, The Way of an Investigator