In the popular mind prolonged starvation is associated with great pain and distress, despite reliable reports to the contrary from many persons who have undertaken voluntary starvation. Such persons state, almost without exception, that after the first three or four days of starvation, the sensation of hunger is no longer felt, or at least is not excessively painful or uncomfortable.
This brings up some important physiological and biological questions. If hunger ceases entirely, or at least loses its painful urge after a few days of starvation, what makes the starving animal fight for food as long as his strength enables him to move ? In man this struggle for food may be due to the desire to live or the fear of death, but can we assume this degree of conscious foresight in the lower animals? Is the reported absence of hunger sensation in man after the first few days of starvation due to failure of the gastric hunger mechanism, or to changes in the brain that prevent the hunger impulses from reaching consciousness? One might naturally expect a decrease in the intensity of the hunger sensation when starvation reaches a point where the brain and stomach are greatly enfeebled by loss of living substance or by too high an acidity of the blood, but this state is not reached in a healthy man by three or four days' deprivation of food. If the hunger mechanism is controlled even in part by the starvation changes in the tissues (stomach, brain) and in the blood, we should expect the hunger sensation to increase in strength up to the point of tissue marked depletion, unless the*starvation itself sets up other inhibitory processes.
These questions can be answered only by direct experiments, • and these were accordingly undertaken both on man and on the lower animals. The work on man was carried out on the author and one assistant (Mr. L.), in such a way that the gastric hunger contractions and the subjective hunger sensation were recorded, day and night, during the entire starvation period. In animals below man we can, of course, record the gastric hunger contractions only, as. we have as yet no means of determining the intensity or quality of the sensations caused by these contractions.
During the five days* starvation period the two men continued their usual work during the day, and records of the stomach tonus and hunger contractions were taken at varying intervals. During the night continuous records were taken beginning 8:00 to 9:00 p.m. and ending at 5:00 to 6:00 a.m. Neither the writer nor Mr. L. found much difficulty in sleeping for 6 to 8 hours every night with balloon and tube in the stomach. The room was kept dark, except for a feeble light focused on the drum, so as to enable the assistant to take care of the recording. And the assistant took special care to keep everything as quiet as possible. One assistant took care of the recording from 8:00 a.m. to 2:00 p.m., and a second assistant from 2:00 p.m. to 6:00 a.m. The time from 6:00 to 8:00 a.m. and from 6:00 to 8:00 p.m. was usually spent in walking in the parks- in any event, outside the laboratory.