By means of the X-rays it is possible to see just what takes place when a fluid is injected into the rectum. For the purpose of determining how nutrient enemata are received and acted upon in the intestines, I have introduced thin, fluid masses in large and small amounts, and thick, mushy masses in large and small amounts, in different animals. The enemata consisted of 100 c.c. of milk, one egg, ten to fifteen grams of bismuth subnitrate, and two grams of starch to hold the bismuth powder in suspension. To make the thick enema all these were stirred together and boiled to a soft mush; to make the thin enema all the parts were boiled together except the egg, which was added after the boiled portion was cooled. The small amount injected was 25 c.c.; the large amount almost 90 c.c., about the capacity of the large intestine when removed from the body. The animals were given first a cleansing injection, and after this was effective the nutrient material was introduced. In order to make sure of the observation, a control radiograph was first taken to show no bismuth food present, and other radiographs taken at varying intervals after the injection to record the course the food was following. [Illustration: 1.50 2.15 3.00 FIGURE 9.—- Radiographs showing that after a large nutrient enema (about 90 c.c.) has been given the food is forced more and more from the large into the small intestine. The enema was introduced at about 1.40 P.M. At 3.00 segmentation was occurring in many loops.] These experiments show that when small amounts of nutrient fluid are introduced they lie first in the descending colon. In every instance antiperistaltic waves are set going by the injection, and the material is thereby carried to the cæcum. When large amounts are injected they stop for a moment in the region between the transverse and descending colon, as if a constriction existed there. Then a considerable amount of the fluid passes the point, and antiperistaltic waves carry it to the cæcum. In any case the repeated passing of the waves seems to have the effect of promoting absorption, for in the region where these waves continue running, the shadows become gradually more dim, and finally the bismuth appears to be only on the intestinal walls; in other regions, _e. g._ in the descending colon, the shadows retain their original intensity. Small injections have never in my experience been forced even in part into the small intestine; but with the larger amounts, whether fluid or mushy, the radiographs show many coils of the small intestine containing the bismuth food.