SECRETION OF GASTRIC JUICE. 439 



The acidity is greatest with a meat diet and lowest with bread; the 

 quantity of enzyme is, on the contrary, highest with a bread diet and 

 lowest with milk. 



The secretion in the stomach may also be influenced by the small 

 intestine, and in this way, as shown by the investigations of PAWLOW 

 and his pupils, the fats have a retarding action upon the secretion of 

 juice and upon digestion by acting reflexly upon the duodenal mucosa. 

 In dogs on feeding fat (oil) with food containing starch, the secretion of 

 gastric juice remains reduced during the entire period of feeding, and fat 

 in connection with protein food has a similar action, with the exception 

 that in this case the retarding action is observed only in the first hours 

 of digestion. According to PIONTKOWSKI 1 the oil-soaps differ from the 

 neutral fats by having a strong action on the flow of juice, and this is 

 the reason why about five to six hours after a meal with fat the secretion of 

 juice is stopped, as just at this time the soaps are being formed. Accord- 

 ing to FROUIN the food in the intestine produces a secretion of gastric 

 juice which continues after the action of the psychic moment has ceased. 

 LECONTE 2 arrived at similar results, and he ascribes a less subordinate 

 importance to the chemical secretion as compared with the psychic 

 secretion, than PAWLOW does. 



The behavior of the different parts of the stomach in secretion is also 

 of interest. The work of PAWLOW and his pupils GROSS and KRYSHY- 

 SCHKOWSKY 3 have shown that meat and its extractives as well as the 

 digestion products and milk especially act upon the pyloric part, although 

 not entirely, while they are inactive upon the fundus. Alcohol also 

 acts upon the fundus part. In close relation to what has been said above 

 stands the observation of EDKINS that the pylorus part of the stomach 

 contains a substance, a prosecretin, which by acids and certain other 

 substances is transformed into a secretin, which when introduced into 

 the blood circulation causes a secretion of gastric juice. HEMMETER,* 

 claims that a secretin for the secretion of gastric juice is also produced 

 in the salivary glands. The extirpation of all the salivary glands in dogs 

 causes a marked diminution in the secretion of gastric juice, while the 

 intravenous or peritoneal injection of an extract of the salivary glands 

 of dogs produces a secretion of gastric juice. 



We know very little positively in regard to the gastric secretion in 

 man. According to the earlier authorities the irritants may be mechanical, 

 thermic, and chemical. Among the chemical excitants we include 

 alcohol and ether, which in too great a concentration bring about no 



1 See Biochem. Centralbl., 3, 660. 



2 Frouin, Compt. rend. soc. biol., 53; Leconte, La Cellule, 17. 



3 Gross, Bioch. Centralbl., 5, 669; Kryshyschkowsky, Maly's Jahresb., 36, 403. 



4 Edkins, Journ. of Physiol., 34; Hemmeter, Bioch. Zeitsclir., 11. 



