184 DIGESTION 



Cannon, the former working chemically and the latter with the Rontgen 

 rays on cats, that the food as swallowed into the stomach may remain 

 in the fundus an hour or more practically undisturbed. This allows 

 amylolytic digestion by the ptyalin to continue, the contents for a time 

 often not being mixed with the hydrochloric acid surrounding it in the 

 stomach wall, and so remaining alkaline. The circular muscular fibers 

 of the stomach's fundus make up the bulk of the musculature and by 

 gradual tonic contraction combined with a slow peristalsis (occurring in 

 the dog in waves three or five times per minute, according to Lommel) 

 the size of the fundus is gradually reduced as its contents are passed 

 through the sphincter of the antrum into the latter portion of the stomach. 

 These gentle peristaltic waves probably are continuous with those 

 descending the esophagus, and they pass from the cardiac end of the viscus 

 to the pyloric valve. Combined with this there may be or not gentle 



FIG. 87 



The human stomach, drawn (from a dissecting-room specimen) so as to make clear the 

 two functional parts of the stomach. (Hutchison.) 



swinging and tipping movements determined by the longitudinal and the 

 oblique fibers of the gastric wall. It is brought about by the full final 

 contraction of the circular fibers of the fundus that when the stomach is 

 empty it has somewhat the shape of a boot (the antrum representing the 

 foot), fixed above by the lower end of the esophagus. The stomach is 

 seen to be an exceedingly adaptable organ so far as its shape is concerned, 

 a faculty which the variety of direction of the muscular fibers makes 

 possible. When nearly empty it is probable that the longitudinal fibers 

 also contract somewhat, still further lessening the size of the viscus. It 

 is thus that the food in the reservoir is gradually and entirely forced 

 onward into the antrum, the walls apparently adjusting themselves 

 perfectly to the volume of their contents. 



The antrum within a few minutes after the ingestion of a meal begins 

 to show slight annular contractions, rhythmic in character, near the 



