DIGESTION AND ABSORPTION IN THE STOMACH. 



773 



quantity but also in their acidity and digestive action. The 

 secretion produced by bread, though less in quantity than that 

 caused by meat, possesses a greater digestive action. On a 

 given diet the secretion assumes certain characteristics, and 

 Pawlow is convinced that further work will disclose the fact 

 that the secretion ot the stomach is not caused normally by general' 

 stimuli all affecting it alike, but by specific stimuli contained in the 

 food or produced during digestion, whose action is of such a kind 

 as to arouse reflexly the secretion best adapted to the food ingested. 

 One of the curves, showing the effect of a mixed diet (milk_, 600 



, Quantity of secretion. 



, Acidity. 



. Digestive power. 



Fig. 295. — Diagram showing the variation in quantity of gastric secretion in the dog after 

 mixed meal; also the variations in acidity and in digestive power. — (After Khigine.) 



CO.; meat, 100 gms.; bread, 100 gms.) upon the gastric secretion, 

 as determined by Pawlow's method, is reproduced in Fig. 295. It will 

 be noticed that the secretion began shortly after the ingestion of the 

 food (seven minutes), and increased rapidly to a maximum that was 

 reached in two hours. After the second hour the flow decreased 

 rapidly and nearly uniformly to about the tenth hour. The acidity 

 rose slightly between the first and second hours, and then fell gradu- 



