ACTION OF THE ENZYMES OF PANCREATIC JUICE 



359 



b, To i c.c. of pancreatic juice (artificial juice is not active), collected in experi- 

 ment 17, add 0.5 c.c. of neutral olive oil, and place over a water bath, c, To 5 c.c. 

 of artificial pancreatic juice add a few flocks of fibrin. Test the digestive 

 action on starch by the iodine test for the disappearance of starch, or by the 

 copper-reduction test for the presence of reducing sugar. Test the fat by its 

 reaction, noting that the neutral or slightly alkaline solution has become acid, 

 also by the fact that an emulsion has been formed. Note that the proteid 

 has gone into solution. 



The digestive action on starch is due to the enzyme amylopsin, or pan- 

 creatic diastase, as it is sometimes called. The fat-splitting effect is due to the 

 enzyme lipase, and the solution of the fibrin is accomplished by the proteolytic 

 enzyme, trypsin. 



21. Conditions which Influence the Action of the Enzymes of 

 Pancreatic Juice. To each of 5 test tubes, a, b, c, d, e, add 5 c.c. of 

 artificial pancreatic juice. Place a, b, c, d in the water bath at 40 C., and e 

 into an ice bath. Leave a normal, make b exactly neutral, add to c i c.c. of 2 

 per cent hydrochloric acid, and boil d. Add to each tube 2 c.c. of i per cent 

 starch paste. Follow the digestive changes by the tests previously outlined. 

 Tabulate according to the following scheme: 



Repeat this experiment with a second set of test tubes containing fibrin. 

 Lipase is not very active in artificial pancreatic juice and may be omitted. 

 If pancreatic juice is available make a third set containing fat. 



22. Cleavage Products of Pancreatic Digestion. To 200 c.c. of arti- 



