MOVEMENTS OF THE STOMACH. 



203 



FIG. 111. Figs. 109, 110, and 111 

 present outlines of the shadow of 

 the contents of the stomach cast on 

 a fluorescent screen by the Rontgen 

 rays. The drawings were made by 

 tracing the outline of the shadow 

 on tissue-paper laid upon the fluor- 

 escent surface, and are about one- 

 half the actual size. They show 

 the change in the appearance of 

 the stomach at intervals of half an 

 hour from the time of eating until 

 the stomach is nearly empty (Am. 

 Jour, of Physiology}. 



and that the constrictions 



in the duodenum. This is spurted 

 through the pylorus and shoots along 

 the intestine for two or three centi- 

 meters. Not every constriction-wave 

 forces food from the antrum. In one 

 of the experiments which were con- 

 ducted by Cannon, about an hour 

 after the movements began, three 

 consecutive waves squirted food 

 into the duodenum. The pylorus 

 remained closed against the next 

 eight waves, opened for the ninth, 

 but closed again for the tenth and 

 eleventh. In this irregular manner 

 the food passed from the stomach. 

 Cannon expresses the opinion that 

 near the end of gastric digestion, 

 when the constrictions are very 

 deep, the pylorus may open for 

 every wave. When a hard bit of 

 food reaches the pylorus, the 

 sphincter closes tightly and re- 

 mains closed longer than when the 

 food is soft. On one occasion, dur- 

 ing these experiments, when a hard 

 particle of food reached the pylorus, 

 the sphincter opened only seven 

 times in twenty minutes. It is 

 inferred from these results that hard 

 morsels keep the pylorus closed and 

 hinder the passage of the food into 

 the duodenum. 



Activity of the Cardiac Portion. 

 The part played by the cardiac por- 

 tion has not hitherto been properly 

 appreciated. It has been regarded 

 as the place for peptic digestion or 

 as a passive reservoir for food ; but 

 it is in fact a most interestingly ac- 

 tive reservoir. Figs. 109-111 rep- 

 resent the appearances the stomach 

 presents at various stages in a diges- 

 tive period. A comparison of them 

 shows that as digestion proceeds the 

 antrum appears gradually to elon- 

 gate and acquire a greater capacity, 

 make deeper indentations in it; but 



