PANCREATIC DIGESTION. I 43 



showing very clearly that a starchy diet is not normal for this period. 



It has been claimed that pancreatic amylase has a slight digestive 

 action upon unboiled starch. 



The third enzyme of the pancreatic juice is called pancreatic 

 lipase (steapsin) and is a fat-splitting enzyme. It has the power 

 of splitting the neutral fats of the food by hydrolysis, into fatty 

 acid and glycerol. A typical reaction would be as follows: 



Tri-palmitin. 'Palmitic acid. Glycerol. 



Recent researches make it probable that fats undergo saponifica- 

 tion to a certain extent prior to their absorption. The fatty acids 

 formed, in part unite with the alkalis of the pancreatic juice and 

 intestinal secretion to form soluble soaps; in part they are doubt- 

 less absorbed dissolved in the bile. Some observers believe that 

 the fats may also be absorbed in emulsion a condition promoted 

 by the presence of the soluble soaps. After absorption the fatty 

 acids are re-synthesized to form neutral fats with glycerol. 



Pancreatic lipase is very unstable and is easily rendered inert 

 by the action of acid. For this reason it is not possible to prepare 

 an extract having a satisfactory fat-splitting power from a pancreas 

 which has been removed from the organism for a sufficiently long 

 time to have become acid in reaction. 



The fourth enzyme of the pancreatic juice is called pancreatic 

 rennin. It is a milk-coagulating enzyme whose action is very 

 similar to that of the enzyme gastric rennin found in the gastric 

 juice. It is supposed to show its greatest activity at a temperature 

 varying from 60 to 65 C. 



The enzymes of the intestinal juice are of great importance to 

 the animal organism. These enzymes include erepsin (erepsase), 

 sucrose, maltasc, lactase, and enterokinase. 



Erepsin is a proteolytic enzyme which has the property of acting 

 upon the proteoses and peptones which are formed through the 

 action of trypsin and further splitting them into amino acids. 

 Erepsin has no power of digesting arty native proteins except 

 caseinogen, histones and protamines. It possesses its greatest ac- 

 tivity in an alkaline solution although it is slightly active in acid 

 solution. An extract of the intestinal erepsin may be prepared by 

 treating the finely divided intestine of a cat, dog, or pig with toluene- 

 or chloroform-water and permitting the mixture to stand with oc- 



