This report of the results of an investigation of 100 patients is a confirmation and, to a degree, an elaboration of previous work of Bockus and his collaborators,1Jones2and others. It scarcely seems necessary to emphasize the importance of the earlier observations of Meltzer3and Lyon,4which were made more than ten years ago. The diagnostic value of duodenal drainage was verified in each case in our series by examination of the gallbladder and its contents at operation and later by gross and microscopic studies made in the department or surgical pathology. METHOD The method advocated by Lyon has not found general acceptance, largely on account of the difficulty and the uncertainty of entering the duodenum. This, we believe, can usually be overcome by the following simplified technic: After a fast of at least six hours the patient is placed in the supine position on