488 



DIGESTION 



The adaptation of the capacity of the normal stomach to the volume of 

 its contents is remarkable. When the stomach of a living animal is dis- 

 tended by fluid the intragastric pressure shows very little change even 

 up to the point of rupture of the viscus (Grey 16 ). After excision, the 

 stomach loses in great part this adaptive power which seems to be con- 

 trolled not through the extrinsic nerves, but by the nervous elements 

 residing in the gastric wall itself. 



The Effect of the Stomach Movements on the Food 



This has been studied: (1) by dividing the food into portions that 

 are differently colored and, after some time, killing the animal, freezing 



Fig. 156. Skiagrams of human stomach at intervals after food illustrating a gastric cycle. 



(From Cole.) 



the stomach and making sections of it (see Fig. 157) ; (2) by mak- 

 ing little pellets of bismuth subnitrate with starch and observing their 

 behavior under the x-rays; or (3) by removing samples of the stomach 

 contents by means of a stomach tube (Rehfuss tube) inserted so that 

 its free end lies in either the cardiac or the pyloric region. By the 

 first of the above methods it has been found that the first mouthfuls 

 of food lie along the greater curvature, where they form a layer over 

 which that subsequently swallowed accumulates, with the last por- 

 tions next the cardia. The pepsin and hydrochloric acid of the car- 



