The sequence of events responsible for the clinical and pathological findings in disease of the stomach is often difficult if not impossible to analyze. The difficulty is directly proportional to the number and complexity of the processes involved. For example, in chronic gastric ulcer one attempts to analyze and properly coordinate the increase or decrease of gastric acidity, secretion, and motility ; pyloric spasm or stenosis ; dilated or hypertrophied stomach, etc. Through long clinical custom certain views are current as to the cause and effect of these interrelating processes, without much question as to the validity of these views or without subjecting them to experimental proof. It has seemed to us that in view of the complexity of the problem of chronic ulcer of the stomach, these several processes should be separated and studied individually, a method, as Bolton1points out, which has not hitherto been adopted. The