[Illustration: Figure 37.--One-half the original size. The top record represents intragastric pressure (the small oscillations due to respiration, the large to contractions of the stomach); the second record is time in minutes (ten minutes); the third record is W’s report of hunger pangs; the lowest record is respiration registered by means of a pneumograph about the abdomen.] This fact may be regarded as evidence that the contraction precedes the sensation, and not _vice versa_, as Boldireff considered it. The contractions were about a half-minute in duration, and the intervals between varied from thirty to ninety seconds, with an average of about one minute. The augmentations of intragastric pressure in Washburn ranged between eleven and thirteen in twenty minutes; I had previously counted in myself eleven hunger pangs in the same time. The rate in each of us was, therefore, approximately the same. This rate is slightly slower than that found in dogs by Boldireff; the difference is perhaps correlated with the slower rhythm of gastric peristalsis in man compared with that in the dog.[207] Before hunger was experienced by Washburn the recording apparatus revealed no signs of gastric activity. Sometimes a rather tedious period of waiting had to be endured before contractions occurred. And after they began they continued for a while, then ceased (see Fig. 38). The feeling of hunger, which was reported while the contractions were recurring, disappeared as the waves stopped. The inability of the subject to control the contractions eliminated the possibility of their being artifacts, perhaps induced by suggestion. The close concomitance of the contractions with hunger pangs, therefore, clearly indicates that they are the real source of those pangs. [Illustration: 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.