Cannon, Walter

Name: Walter Bradford Cannon

Achievements: Investigations into homeostasis

Born: October 19, 1871; Prairie du Chien, Wisconsin

Died: October 1, 1945; Franklin, New Hampshire (Aged 74)

Field & Discipline: Medicine; Physiology

Language: English

Father: Father: Colbert Hanchett Cannon

Mother: Sarah Wilma Denio

Siblings: Unknown

Spouse: Cornelia James

Children: 5

Education: Public schools in Milwaukee and St Paul; Harvard College; Harvard Medical School

Major Work:

“The Mechanical Factors of Digestion” (1911)

“Bodily Changes in Pain, Hunger, Fear and Rage” (1915)

“Traumatic Shock” (1923)

“Autonomic Neuro-Effector Systems” (with Arturo Rosenblueth, 1937)

Life & Times:

Cannon’s father was a railroad official who took him out of school at age 14, and made him work in a railroad office. At the age of sixteen Cannon returned to school where he did so well that he got a scholarship to Harvard,  where he studied the biological sciences.  One of his most influential tutors at Harvard was the psychologist [taught by] William James* and during his time at Harvard Cannon became interested in neurology and psychology.

In 1896 when he was twenty-five he joined the medical school at Harvard and began a research project using the X-rays recently discovered by [influenced by] Roentgen* to investigate the mechanism of swallowing. In December of that year he and his co-researcher demonstrated the swallowing mechanism of a goose before the American Physiological Society in Boston. This was the first public instance of alimentary motion demonstrated by X-ray.

Cannon also pioneered new teaching methods. He had become extremely fed up with the current system of sitting through hours and hours of dry lectures five days a week, and he envied his law student friends who used actual law cases as a basis for teaching. His paper “Case Method of Teaching Systematic Medicine” (1900) was favorably received and the system of teaching by studying and debating case histories was adopted at Havard.

In 1901 when he proposed to his future wife, Cannon sent her an X-ray picture showing his hand held over his heart. He was appointed instructor of physiology at Harvard, made an assistant professor in 1902 and in 1906 became Professor of Physiology and director of the Department of Physiology at Harvard Medical School, a post in which he remained until his retirement. While continuing his gastrointestinal researches using radiography, Cannon also became involved with defending medical researchers against the charges of the antivivisectionists. In 1908 he was appointed chairman of the Defense Committee in Support of Medical Research and he mounted a robust defense of vivisection.

In 1911 he published the results of his innovative work on the alimentary canal in “The Mechanical Factors of Digestion”. During the course of his research he had noticed that movements in the alimentary canals of animals were inhibited during a state of emotional excitation. This led him to investigate the fight or flight phenomenon in humans and animals which is caused by the release of adrenaline, and the actions of the sympathetic nervous system. In 1915 he published “Bodily Changes in Pain, Hunger, Fear, and Rage” in which he noted that international athletic competitions could harness aggressive behavior and provide “a physiological equivalent for war”.

In 1916 Cannon was made a member of a national committee on traumatic shock and when America entered the first world war a year later he joined the Harvard University Hospital Unit. He worked with English colleagues on trauma research in London before taking up a post as director of a surgical research laboratory attached to the American Expeditionary Forces in Dijon, France. He later wrote up his wartime experiences in “Traumatic Shock” (1923).

After the war, Cannon resumed his research on the sympathetic nervous system. He was exceptionally skilled in surgical procedures and his dexterity allowed him to remove the sympathetic nerves of an animal and observe the effect. Innovative experiments with a denervated cat heart led him to the discovery that stimulation of the nerves in the liver produced an acceleration in the denervated heart. Similar effects, obtained by stimulating other sympathetic nerves, implied that there was an unknown factor or chemical substance that organized the transmission of nerve impulses – a fact which was confirmed by the discoverers of chemical neurotransmission (Henry Dale and Otto Loewi) in the 1930’s.

During the 1920’s Cannon investigated his idea that the function of the autonomic nervous system is to maintain the  relatively stable interior condition necessary to the survival of organisms, a condition named the “milieu interieur” by the French physiologist [influenced by] Bernard*.

In 1926 Cannon used the word [coined the term] “homeostasis”* to describe the uniform interior state of  organisms and the physiological processes involved in maintaining this state. In 1929 he published a paper on homeostasis reviewing the homeostatic regulation in organisms of water and sodium chloride balance, glucose, protein, fat and calcium, and also examining the role of the autonomic nervous system in homeostasis and the effects of hunger, thirst and temperature.  His conclusion that regulation was the “central problem of physiology” had a major influence on future biological research. His ideas entered the popular domain when he published a book in 1932 entitled “Wisdom of the Body” in which he extended the concept of homeostasis to stability in society.

During the 1930’s, in collaboration with the Mexican physiologist [collaborated with] Rosenblueth*, Cannon concentrated on the study of chemical transmission of nerve impulses. In “Autonomic Neuro-Effector Systems” (1937) they stated their hypothesis that there were two substances which affected the sympathetic nerves, one excitatory and the other inhibitory (these substances are now known to be epinephrine and norepinephrine).

Cannon maintained contact with many scientists from abroad, including the [corresponded with] Russian Ivan Pavlov* whose work on digestion was similar to Cannon’s own investigations. In 1935 Cannon attended a physiological conference in Moscow at Pavlov’s invitation and while he was there gave a speech stressing the relevance of civil liberties for advances in research.

In 1937 he became national chairman of the Medical Bureau to Aid Spanish Democracy whose aim was to provide medical aid to those in need during the unrest which led to Civil War in Spain. After the fascist victory Cannon was involved in finding safe havens for those scientists and medical personnel who had fought against General Franciso Franco and later extended these efforts to include scientists and doctors threatened by the Nazi regime in Germany.

When World War II  broke out in 1939 Cannon became chairman of the Committee on Shock and Transfusion of the National Research Council. He retired from the medical school at Harvard in 1942. During his last years he suffered from illnesses related to his early radiographic research.

Extra Connections: Parlin*?

Assessment: Cannon’s studies of homeostasis were of great significance not only for physiologists but also in the fields of endocrinology and pyschology.

Bibliography:

• American National Biography.
• Dictionary of Scientific Biography.