DIGESTION AND ABSORPTION IN THE STOMACH. 



783 



Starling* has emphasized the fact that this mode of control is 

 frequently employed in the body, as will be described in the 

 following pages in connection with the pancreatic secretion and 

 the internal secretions. He proposes to designate such sutn 

 stances by the general term of hormones (from oppaw, arouse 

 or excite). Leaving aside for the moment the way in which 

 the secretogogues excite the secretion it is important to empha- 



Quantity of secretion. 

 Acidity. 

 Digestive power. 



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

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



size the fact that in the normal secretion of gastric juice, that 

 is to say, in the secretion which takes place during an ordinary 

 meal, we must distinguish between a nervous secretion due to 

 the action of the secretory fibers in the vagus, and a chemical 

 secretion due to the chemical stimulation of the secrotogogues or 

 of the hormones produced by them. 



The researches of Pawlow and his co-workers seem also to in- 

 dicate that the quantity and properties of the secretion vary with 

 the character of the food. The quantity of the secretion varies, 

 also, other conditions being the same, with the amount of food to 



* Starling, "Recent Advances in the Physiology of Digestion," 1906. 



