EFFECT OF NERVOUS DISTURBANCES. 207 



part of the stomach is fully relaxed. A flattening of the dia- 

 phragm and a quick jerk of the abdominal muscles, accompanied 

 by the opening of the cardia, next force the contents of the fundus 

 into the esophagus. As the spasmodic contractions of the abdomi- 

 nal muscles are repeated, the gastric wall again tightens around 

 the contained food. Cannon has seen antiperistalsis but once, 

 when a constriction started at the pylorus and ran back, over the 

 antrum, completely obliterating the antral cavity. 



In the discussion of the movements of the stomach we have 

 quoted largely from the paper of Cannon, and desire here to 

 express our admiration of what we regard as one of the most 

 valuable contributions to the physiology of the stomach since the 

 time of Dr. Beaumont, and in concluding this part of the subject 

 we quote the following statement and summary. He says : 



" Although my observations do not support their (Beaumont 

 and Brinton) theories of mixing currents running throughout the 

 stomach, they still show that the pyloric portion is an admirable 

 device for bringing all of the food under the influence of the 

 glandular secretions of that organ. For, when a constriction 

 occurs, the secretory surface enclosed by the ring is brought close 

 around the food lying within the ring in the axis of the stomach. 

 As this constriction passes on, fresh areas of glandular tissue are 

 continuously pressed in around the narrow orifice. And also, as 

 the constriction passes on, a thin stream of gastric contents is 

 continuously forced back through the orifice and thus past the 

 mouths of the glands. The result of this ingenious mechanism 

 is that every part of the secretory surface of the pyloric portion 

 is brought near to every bit of food before the latter leaves the 

 stomach, a half hundred times or more." 



"Summary. 1. By mixing a harmless powder, subnitrate of 

 bismuth, with the food, the movements of the stomach can be 

 seen by means of the Rontgen rays. 



" 2. The stomach consists of two physiologically distinct parts : 

 The pyloric part and the fundus ; over the pyloric part, while 

 food is present, constriction-waves are seen continually coursing 

 toward the pylorus ; the fundus is an active reservoir for the food, 

 and squeezes out its contents gradually into the pyloric part. 



" 3. The stomach is emptied by the formation, between the 

 fundus and the antrum, of a tube along which constrictions pass. 

 The contents of the fundus are pressed into the tube, and the 

 tube and antrum slowly cleared of food by the waves of con- 

 striction. 



"4. The food in the pyloric part is first pushed forward by 

 the running wave, and then, by pressure of the stomach-wall, is 

 returned through the ring of constriction ; thus the food is 

 thoroughly mixed with gastric juice, and is forced by an oscil- 

 latory progress to the pylorus. 



