For many years it has been generally recognized that pyloric stenosis exerts an unfavorable influence on the healing of chronic duodenal and gastric ulcers. Sippy1 was persuaded that this unfavorable effect could not be accounted for simply by malnutrition resulting from the vomiting induced by obstruction at the pylorus. In 1914 Friedman and Hamburger2 provided experimental evidence in support of this view. They demonstrated that the injection of 0.5 to 1 cc of a 5% solution of silver nitrate beneath the mucous membrane of the stomach or duodenum would produce localized necrosis of the mucosa and a sharply punched out acute ulcer. If nothing further was done, these acute lesions healed in two to three weeks, an observation that we have repeatedly confirmed. However, if partial pyloric obstruction was produced by placing a heavy silk ligature around the pylorus of dogs, such acute lesions in the stomach produced