Page:Popular Science Monthly Volume 81.djvu/308

302 his observation of the phenomenon. Six years ago Boldireff demonstrated that the whole gastro-intestinal tract has a periodic activity while not digesting. Each period of activity lasts from 20 to 30 minutes, and is characterized in the stomach by rhythmic contractions 10 to 20 in number. These contractions, Boldireff reports, may be stronger than during digestion, and his published records clearly support this statement. The intervals of repose between periodic recurrences of the contractions lasted from one and a half to two and a half hours. Especially noteworthy is Boldireff's observation that if fasting is continued for two or three days, the groups of contractions appear at gradually longer intervals and last for gradually shorter periods, and thereupon, as the gastric glands begin continuous secretion, all movements cease.

Observations Suggesting a Relation Between Contractions and Hunger.—When Boldireff's paper was published I was studying auscultation of abdominal sounds. Repeatedly there was occasion to note that the sensation of hunger was, as already stated, not constant, but recurrent, and that its momentary disappearance was often associated with a rather loud gurgling sound, as heard through the stethoscope. That contractions of the alimentary canal on a gaseous content might explain the hunger pangs seemed probable at that time, especially in the light of Boldireff's observations. Indeed, Boldireff himself had considered hunger in relation to the activities he described, but solely with the idea that hunger might provoke them; and since the activities dwindled in force and frequency as time passed, whereas, in his belief they should have become more pronounced, he abandoned the notion of any relation between the phenomena. Did not Boldireff misinterpret his own observations? When he was considering whether hunger might cause the contractions, did he not overlook the possibility that the contractions might cause hunger? A number of experiences have led to the conviction that Boldireff did, indeed, fail to perceive part of the significance of his results. For example, I have noticed the disappearance of a hunger pang as gas was heard gurgling upward through the cardia. That the gas was rising rather than being forced downward was proved by its regurgitation immediately after the sound was heard. In all probability the pressure that forced the gas from the stomach was the cause of the preceding sensation of hunger. Again the sensation can be momentarily abolished a few seconds after swallowing a small accumulation of saliva or a teaspoonful of water. If the stomach is in strong contraction in hunger, this result can be accounted for as due to the inhibition of the contraction by swallowing. Thus also could be