Two other movements have been observed in the ascending colon, but they are rare appearances. The first of these was a serial sectioning of the contents noticed in an animal given castor oil with the food. A constriction separated a small segment in the cæcum; another constriction then cut off a segment just above the first, and with the disappearance of the first constriction the two separated segments united. A third segmentation took place above the second, and the changes occurred again. Thus the whole mass was sectioned from one end to the other; and no sooner was that finished than the process began again and was repeated several times. A slight modification of this movement was observed in a colon containing very little food. The mass was pressed and partially segmented in the manner characteristic of the small intestine, and was thus again and again spread along the ascending colon, and each time swept back into a rounded form by antiperistalsis. The second of the two movements mentioned above consisted in a gentle kneading of the contents. This was caused by broad constrictions appearing, relaxing, appearing, relaxing, over and over again, in the same place. When several of these regions were active at the same time, they gave the food in the colon the appearance of a restless undulatory mass. Once a constriction occurred and remained permanently in one place, while the bulging parts on either side of it pulsated alternately, at the rate of about eighteen times in a minute, with the regularity of the heart-beat. Although these phenomena are somewhat striking, they are not usual, and are in no way so important as the antiperistalsis. _The changes when food enters the colon._--The passage of food through the ileocæcal valve seems to stimulate the colon to activity. As food is nearing the ileocæcal valve the large intestine is usually quiet and relaxed (Fig. 6, 4.00), though occasionally indefinite movements are to be observed; and sometimes just before the food reaches the end of the ileum the circular fibres of the colon in the region of the valve contract strongly, so that a deep indentation is present there. The indentation may persist several minutes; it disappears as the muscles relax just previous to the entrance of the food. The food is moved slowly along the ileum and is pushed through the valve into the colon. The moment it has entered a strong contraction takes place all along the cæcum and the beginning of the ascending colon, pressing some of the food onward, and a moment later deep antiperistaltic waves (Fig. 6, 4.03) sweep down from the transverse colon and continue running until the cæcum is again normally full, _i. e._, for two or three minutes. [Illustration: FIGURE 6.--Tracings showing changes when food enters the colon and also the first tonic constriction. 4.00, the colon relaxed as food approaches in the ileum. 4.03, the colon contracted and traversed by antiperistaltic waves after the food has entered.]