Cannon, America’s foremost physiologist, was associated with the Harvard Medical School during his entire career—first as student, then as instructor and professor. His professional contributions began when he became the first investigator to use X rays in the study of the gastric process. This technique enabled him to observe the motility function of the gastrointestinal tract, which he later described in a book entitled The Mechanical Factors of Digestion (1911). His studies of the digestive system, which he carried out with Anton J. Carlson, also led to the theory that hunger was due to contractions of an empty stomach. This so-called local theory of hunger was directly opposed to the prevailing theory which explained this sensation in terms of a response by brain mechanisms to nutritive deficiencies in the blood. He also advanced a local theory of thirst, which he attributed to a dry mouth caused by lack of saliva flow. See HUNGER, THIRST.Cannon’s greatest contributions arose out of his studies of the bodily changes that take place in emotion. He showed that in fear, rage, and other intense emotional states respiration rate, blood pressure, and heartbeat are sharply increased, while the digestive processes are inhibited. He further demonstrated that these changes are mediated by the sympathetic nervous system through an increase in the secretion of adrenalin into the bloodstream. In a word, the two systems, sympathetic and adrenal, work together to put the organism on a “war footing” and prepare it for “fight or flight.” This new theory was advanced in 1915 in a book entitled Bodily Changes in Pain, Hunger, Fear and Rage.Further studies led to an elaboration of this theory of emotion. Cannon found that when he stimulated certain parts of the brains of animals, they responded with ragelike behavior; and extirpation experiments conducted by his pupil Philip Bard, indicated that the thalamus was the actual control center. From these and other experiments Cannon and Bard developed the theory that the thalamus directly affects the cortex and the muscles and, through the autonomic nervous system, the visceral organs as well. This center appeared to be implicated in the entire pattern of bodily changes in emotion, and for this reason the new concept became known as the thalamic theory. See EMOTION (THEORIES).These early investigations led Cannon to a broader investigation of the body’s reactions to stresses and disturbances. In a book published in 1932, The Wisdom of the Body, he documented the astounding number and complexity of physiological mechanisms that enable the organism to maintain a constant internal state even when it is subjected to radical changes in the external environment. He applied Claude Bernard’s term “homeostasis” to the co-ordination of functions that makes this stability possible, and he demonstrated that the sympathico-adrenal system is of utmost importance in this process. This he did by showing that when this system is removed, animals will be able to maintain themselves only if the environment makes very few demands on them. See HOMEOSTASIS.Cannon made many other major contributions, which he reported in a number of books and over 200 journal articles. His study of surgical shock, which he carried out in the laboratory and near the front lines, is credited with saving many lives during World War I. His new findings were later described in a book Traumatic Shock (1923). Another book, Autonomic Neuro-Effector Systems, written in collaboration with A. Rosenblueth (1937), added substantially to our knowledge of the autonomic nervous system and the way nerve impulses are transmitted to peripheral organs.Cannon did not confine himself to the laboratory, but took a deep interest in social matters. Among his contributions in this sphere was his conception of a society that would provide an environment in which the individual could not only maintain himself but realize his fullest potential. He held that such a society must have built-in mechanisms for handling economic and natural calamities that threaten its “homeostasis.” In a word, he believed that the principles he had discovered for the biological organism could also be applied to the social organism.CAPGRAS SYNDROME. A rare psychotic disorder in which the patient insists that other individuals are not really themselves, but are “doubles” or impostors.The reaction was first described in 1923 by the French psychiatrist J. Cap- gras, who termed it “L’illusion des sosies” (the illusion of doubles). His patients were all women, but more recently a few male cases have been reported in this country. French psychiatrists consider the condition a syndrome, or disease entity, in itself, but American and German authors generally view it as a special symptom of paranoid schizophrenia, paranoid state, or less often, manic-depressive reaction.Davidson (1941) interprets the reaction as a form of magical thinking which serves the unconscious purpose of rejecting important persons in the patient’s life. Arieti and Meth (1959) also believe it is a form of rejection, but make the further point that the double serves as a target for resentments felt against the person whose existence is being denied. If, for example, a female patient is confronted by her mother, but insists that she is an impostor, the reason is that “the patient rejects the mother, actually attributes very bad habits to her, but cannot allow herself to become conscious of this rejection because of concomitant feelings of guilt or other ambivalent attitudes. What the patient feels about the mother is thus displaced to the double or impostor who allegedly assumes her appearance.” In other words, the patient can still maintain the fiction that her mother is a model of virtue, while giving vent to her true feelings against the double.The following is an excerpt from the case of a seventy-three-year-old man who had been diagnosed as a schizophrenic, paranoid type, subject to auditory hallucinations of a persecutory and threatening character. These symptoms subsided during long hospitalization, but he developed a typical Capgras reaction toward his wife and others:Since the writer has known the patient, the man always has made a good appearance, clean-shaven, very neat in dress, polite in conversation. He seems much younger than his age, shows remarkable preservation of personality; there are no feet symptoms. His memory is unusually good, with the exception of memory falsifications which are in harmony with his delusional content. As far as the problems studied here are concerned, he gave additional information. He said that he had never cared for his wife. For some three years before his admission, he asserted, he had noticed she was changing considerably. He recalled that one day when she was undressed her skin appeared to him gray and like a cow’s udder. He thought that the power of the devil displaced her in the form of a double. Once this double came to the hospital and asked him what he did for sexual intercourse; and when he was horrified by the question, the double advised him to commit suicide. In response to this, he told her to run for her life, since he would kill and get away with it, being considered insane. A week later, he said, the “true” wife visited him. When he asked her about the conversation of the last visit, she denied any knowledge of it. Further “proof” for the existence of the double was his assertion that his wife, on the day of the visit of the double, was in Connecticut.The man identified other doubles as well. One took the place of a male stenographer. Another displaced the physician in charge of the city psychopathic hospital; as proof of this, the patient had two photographs of the person in question cut out from newspapers. He declared that the true head of the hospital was a kindly man, while the double was cruel, committing people to state hospitals. Still another double replaced a hospital clergyman. The patient, therefore, stopped going to church, saying that after all he was a priest himself and was able to say mass daily himself.” (Davidson, 1941)

Cite this page: N., Sam M.S., "CANNON, WALTER BRADFORD (1871-1945)," in, November 28, 2018, (accessed January 19, 2022).


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