Bodily changes in pain, hunger, fear, and rage

by Walter B. Cannon

Figure 38.—One-half the original size. The same conditions as in [Fig. 37]. (Fifteen minutes.) There was a long wait for hunger to disappear. After x, W. reported himself “tired but not hungry.” The record from y to z was the continuance, on a second drum, of x to y.

Boldireff’s studies proved that when the empty stomach is manifesting periodic contractions, the intestines also are active. Conceivably all parts of the alimentary canal composed of smooth muscle share in these movements. The lower esophagus in man is provided with smooth muscle. It was possible to determine whether this region in Washburn was active during hunger.

To the esophageal tube a thin-rubber finger-cot (2 centimeters in length) was attached and lowered into the stomach. The little rubber bag was distended with air, and the tube, pinched to keep the bag inflated, was gently withdrawn until resistance was felt. The air was now released from the bag and the tube farther withdrawn about 3 centimeters. The bag was again distended with air at a manometric pressure of 10 centimeters of water. Inspiration now caused the writing lever, which recorded the pressure changes, to rise; and a slightly farther withdrawal of the tube changed the rise, on inspiration, to a fall. The former position of the tube, therefore, was above the gastric cavity and below the diaphragm. In this position the bag, attached to a float recorder (with chamber 2.3 centimeters in diameter), registered the periodic oscillations shown in [Fig. 39]. Though individually more prolonged than those of the stomach, these contractions, it will be noted, occur at about the same rate.

Figure 39.—One-half the original size. The top record represents compression of thin rubber bag in the lower esophagus. The pressure in the bag varied between 9 and 13 centimeters of water. The cylinder of the recorder was of smaller diameter than that used in the gastric records. The esophageal contractions compressed the bag so completely that, at the summits of the large oscillations, the respirations were not registered. When the oscillations dropped to the time line, the bag was about half inflated. The middle line registers time in minutes (ten minutes). The bottom record is W’s report of hunger pangs.

This study of hunger, reported by Washburn and myself in 1912, has since been taken up by Carlson of Chicago, and in observations on a man with a permanent gastric fistula, as well as on himself and his collaborators, he has fully confirmed our evidence as to the relation between contractions of the alimentary canal and the hunger sensation. In a series of nearly a score of interesting papers, Carlson and his students[38] have greatly amplified our knowledge of the physiology of the “empty” stomach. Not only are there the contractions observed by Washburn and myself, but at times these may fuse into a continuous cramp of the gastric muscle. The characteristic contractions, furthermore, continue after the vagus nerve supply to the stomach has been destroyed, and, therefore, are not dependent on the reception of impulses by way of the cranial autonomic fibres. Recently Luckhardt and Carlson have brought forward evidence that the blood of a fasting animal if injected into the vein of a normal animal is capable of inducing in the latter the condition of cramp or tetanus in the gastric muscle mentioned above—an effect which does not occur when the blood of a well-fed animal is injected. It seems possible that a substance exists in the blood which acts to excite the gastric hunger mechanism. But this point will require further investigation.

With these demonstrations that contractions are the immediate cause of hunger, most of the difficulties confronting other explanations are readily obviated. Thus the sudden onset of hunger and its peculiar periodicity—phenomena which no other explanation of hunger can account for—are at once explained.

In fever, when bodily material is being most rapidly used, hunger is absent. Its absence is understood from an observation made by F. T. Murphy and myself,[39] that infection, with systemic involvement, is accompanied by a total cessation of all movements of the alimentary canal. Boldireff observed that when his dogs were fatigued the rhythmic contractions failed to appear. Being “too tired to eat” is thereby given a rational explanation.

A pathological form of the sensation—the inordinate hunger (bulimia) of certain neurotics—is in accordance with the well-known disturbances of the tonic innervation of the alimentary canal in such individuals.

Since the lower end of the esophagus, as well as the stomach, contracts periodically in hunger, the reference of the sensation to the sternum by the ignorant persons questioned by Schiff was wholly natural. The activity of the lower esophagus also explains why, after the stomach has been removed, or in some cases when the stomach is distended with food, hunger can still be experienced. Conceivably the intestines also originate vague sensations by their contractions. Indeed, the final banishment of the modified hunger sensation in the patient with duodenal fistula, described by Busch, may have been due to the lessened activity of the intestines when chyme was injected into them.