REGULATION OF THE PANCREATIC SECRETION, 225 



the hydrochloric acid a second time, when figures practically 

 the same as those given above can again be obtained. Phos- 

 phoric, citric, lactic, and acetic acid behave in a way similar 

 to hydrochloric. Carbonic acid also belongs in this group. 



Sodium chloride in solution seems to be without effect 

 upon the pancreas, and alkaline solutions, such as calcium 

 hydroxide, sodium bicarbonate, and alkaline mineral waters, 

 have a distinctly inhibitory effect upon its secretion. 



After what has been said it is not strange that gastric juice 

 acts as a chemical excitant of the pancreas, and to the same 

 degree as a hydrochloric acid solution of the same concentra- 

 tion. When the gastric juice of the acid food passing out 

 of the stomach is neutralized the effect of the latter in calling 

 forth a pancreatic secretion disappears. In what way the 

 acid is effective in acting upon the pancreas will be discussed 

 later when we speak of secretin. 



In spite of the fact that starch is one of the constituents of 

 the food upon which the pancreatic juice acts, this carbohy- 

 drate, whether boiled or unboiled, and at any concentration, 

 affects the quantity of juice poured out by the pancreas no 

 more than an equal amount of water. A qualitative change 

 in its composition is, however, rendered probable by the ex- 

 periments of WALTHER, who found that a dog when fed on 

 bread secretes a pancreatic juice richer in amylolytic ferment 

 than when fed with meat. 



Fat seems to be an excitant of the pancreas. DOLINSKI 

 and DAMASKIN l found that after introducing oil into the 

 stomachs of dogs a flow of pancreatic juice always ensued. 



Do we have a psychic secretion of pancreatic juice similar 

 to the psychic secretion of gastric juice? This question can- 

 not yet be looked upon as definitely settled. KUWSCHINSKI 2 

 showed in 1888 that tempting a hungry dog with food led 



1 PAWLOW : Work of the Digestive Glands. Translated by THOMPSON, 

 London, 1902, p. 121. 



2 KUWSCHINSKI : PAW LOW'S Work of the Digestive Glands. Trans- 

 lated by THOMPSON, London, 1902, p. 121, 



