Present day apparatus and technic have increased the frequency with which the crater of a doudenal ulcer can be demonstrated. Many investigators still feel that duodenal deformity is sufficient for the diagnosis of ulcer and make no attempt to determine the absence or presence of crater. The demonstration of crater not only establishes activity but, as in the case of gastric ulcer, is useful in following the healing during a course of medical treatment. DEFORMITY Deformity of the duodenal bulb is an indirect sign that may occasionally result from extraneous influences,1may not be demonstrable even in the presence of a rather large crater, gives no objective clue as to the presence of active or healed ulcer and may decrease, remain stationary or increase, with resulting stenosis, during a course of medical treatment. In rare instances the deformity may be caused by adhesions or invasion of the duodenum by