THE PANCREATIC JUICE 



789 



A. Secretin juice from three dogs. Sp. gr. 1014. 



B. Secretin juice, specimen collected at beginning (a), and at end (b). 



C. Pilocarpine juice. 



into three groups, a small amount of nucleo-protein precipitated 

 on acidification, a protein coagulating at 55 C., and another at 

 about 75 C. The juice tends to become poorer in proteins and 

 richer in alkali as secretion proceeds. The concentrated juice obtained 

 by injection of pilocarpin, which may contain as much as 6 per cent, 

 total solids, is always considerably less alkaline than the more dilute 

 juice got by injection of secretin. The most interesting and important 

 constituents of the juice are its ferments or precursors of ferments. 

 The juice on arrival in the intestine has, or develops, an effect on 

 all three classes of food- stuffs, namely, proteins, fats, and carbo- 

 hydrates. 



ACTION ON PROTEINS 



Although the digestive action of pancreatic juice on proteins 

 was pointed out by Corvisart, little attention was paid to this action 

 either by Claude Bernard or subsequent authorities until Kiihne 

 subjected the action of extracts of the gland to a thorough investiga- 

 tion. The neglect of this action by Claude Bernard must be ascribed 

 to the fact that he worked with pancreatic juice. It has been shown 

 more recently that pancreatic juice as secreted is free from proteo- 

 lytic effects, and that for the development of this power it is necessary 

 that some change should be brought about in the juice itself, namely, 

 a conversion of trypsinogen into trypsin. This change under normal 

 circumstances is brought about directly the juice enters the gut, 

 by the action of a substance enterokinase contained in the succus 

 entericus. The pancreatic juice thereby acquires a proteolytic 



