THE REGULATION OF GASTRIC SECRETION. 211 



water alone was injected, bring about not even a slight secre- 

 tion of gastric juice. This salt is, therefore, to be looked 

 upon as inhibiting the gastric flow, for its presence prevents 

 the usual exciting effects of the water alone. Oils also have 

 a distinct inhibitory effect, according to LOBASSOFF. 



Uncoagulated white of egg, whether diluted with water or 

 not, never brings about a greater secretion of gastric juice 

 than the same volume of pure water. This is an altogether 

 unexpected fact, and points to the importance of the appetite 

 juice in normal digestion. Neither does starch, boiled or un- 

 boiled and variously diluted, nor grape-sugar, nor cane-sugar, 

 excite the stomach to secrete juice. Even bread and boiled 

 white of egg remain for hours in the stomach and excite no 

 gastric secretion if the psychic element is shut out. 



Certain commercial peptones will excite the gastric mucous . 

 membrane directly, but by no means all of them. Pure 

 peptones do not, however, have this effect. We are in 

 consequence driven to the conclusion that the commercial 

 peptones contain as yet unknown chemical substances 

 which are the real excitants of the gastric flow. Meat broth, 

 meat juice, and solutions of meat extract act as constant and 

 active excitants of the gastric secretion. Meat also belongs 

 in this group, but all these substances bring on a flow of gas- 

 tric juice much later than when sham feeding is practised. 

 Whereas the latter method shows a beginning of secretion 

 after 5 minutes, the former is without effect for 15 to 45 

 minutes afterward. The majority of foodstuffs does not, 

 therefore, affect the secretion of gastric juice. To the 

 minority which is active in this direction, water and cer- 

 tain as yet unknown constituents of meat belong. The 

 manner in which these are effective is now to be discussed. 

 > 7. Gastric Secretin. When we study the quantitative 

 variations in the secretion of gastric juice, we note that 

 the curve of secretion shows two maximal points. The first 

 of these is observed immediately after the ingestion of food, 

 the second two or three hours later. The rapid secretion 



