THIS subject is far from settled and unanimity of opinion is still being sought in the interpretation of duodenal motility. Various clinicians are attributing symptom-complexes to supposedly pathologic contractions of the duodenum (19), and are suggesting operative procedures as a cure. Certainly a disturbance demanding such radical treatment cannot be studied too carefully or too frequently. The following impressions are the result of five years of observation. At first, all gastric cases were observed and studied and notes were made on the motility, form, and size of the duodenal curve. This group comprises well over two thousand cases studied at the Cook County Hospital. Later, as comparative studies became necessary, five other groups were added. These were as follows: 1. Visceroptosis with no abdominal complaints, 50 cases. 2. Hypertonicity with no abdominal complaints, 50 cases. 3. Proven gall-bladder pathology, 50 cases. 4. Gastric ulcer, 25 cases. 5. Active duodenal ulcer, 100 cases. Before one can appreciate the possible disturbances in motility in the duodenum, a short review of the anatomic relations is necessary (8). The first portion, or duodenal cap, usually leads upward and obliquely backward into the descending portion. The second portion comes in relation with the gall bladder, so that infections in this organ have been frequently blamed for stasis and surging in the duodenal curve. The third, or horizontal, portion crosses the spine and the aorta, and lies underneath the mesentery and superior mesenteric artery. Various authors have attributed apparent obstructive signs to a narrowing of the opening at the duodenojejunal flexure, at which the ligament of Treitz is found. Many peritoneal folds have been described, but they are rather rare and of little importance. Plain muscular fibers have been delineated in the ligament of Treitz. The possibility of sphincteric action at this point will be considered later. The nerve supply of the duodenum arises in the solar plexus, but there is also an intrinsic nerve supply from the Meissner plexus. This double nerve control may account for some of the variations seen in normal cases. In the study of our cases, careful notes were taken of the size of the duodenal cap, the angle formed by the cap and the descending portion, which we have called the cap angle, the size of the descending portion, the course over the spine, the length and steepness of the ascending portion, which we have called the duodenal climb, and the angle at the duodenojejunal junction, which we have called the Treitz angle. Observers at different times have pointed to all of these anatomic divisions as the locations of frequent obstructions. Keeping this in mind, we studied the flow of the barium through these areas with and without manual aid, and in the upright, horizontal, and reversed Fowler positions. Visceroptosis with No Abdominal Complaints In the normal hypotonic individual, the duodenal curve is usually “V”-shaped.