The early writings on the subject of gastric movements are characterised by general inferences from physical laws and from the anatomical structure of the stomach. According to Galen the stomach had four functions: to draw the food from the mouth (_facultas attractrix_), to retain the food (_facultas retentrix_) during the process of chemical digestion (_facultas alteratrix_), and, finally, to pass the changed material onward (_facultas expultrix_). In later writings the _facultas attractrix_ failed to appear as one of the functions of the stomach. Fallopius, in the sixteenth century, changed the notion of the _facultas retentrix_ by suggesting that the pylorus alone performed this office, and that the muscles of the gastric wall could help only by remaining quiet. Thus the _facultas alteratrix_ and the _facultas expultrix_ are left as true gastric functions. It is with the latter activity and its effects that this paper is concerned. The ideas of the early writers concerning the pylorus and cardia are of interest. The cardia, they were agreed, is closed during normal digestion in order to keep the food from re-entering the œsophagus. The pylorus they looked upon as the ruler of the actions of the stomach. Such names as pylorus (keeper of the gate), janitor justus, and rector, which the first investigators gave to the sphincter, indicate their theories of its functions. The passage of chyme into the duodenum, the keeping of undigested food in the stomach, the act of vomiting, were all dependent, they believed, on the “will” of the pylorus. No substantial advance was made beyond these hypotheses until the beginning of the eighteenth century, when Wepfer and Schwartz applied the experimental method to the study of the gastric movements and laid the foundation of a more accurate knowledge. Wepfer vivisected wolves, dogs, and cats, and observed constrictions following stimulation of the stomach. He remarked a general contraction of the pyloric part in vomiting and noted peristaltic and antiperistaltic movements passing over the organ. About the middle of the stomach he frequently saw a deep constriction. The investigations of Schwartz are more valuable in that his search was for the normal action of the muscular coats. The movements, as he observed them, were generally only slight. They began either at the pylorus and passed to the left, half-way to the cardia, or started at the fundus and went to the pylorus. The contractions and relaxations, following one another, formed larger or smaller depressions and elevations, _i. e._, more or less definite waves.