ORGANS AND PROCESSES OF DIGESTION 63 



put 10 c.c. of solution of pancreatin, and some minced white 

 of egg. Label Tubes 1, 2, 3, 4, and 5. To Tube 4 add 5 c.c. 

 of hydrochloric acid and to Tube 5 add 5 c.c. of caustic 

 soda solution. Keep Tubes 1, 4, and 5 at 36 C., Tube 2 

 on ice, and Tube 3 in boiling water for twenty-four 

 hours. 



At the end of twenty-four hours examine all the tubes and 

 note in which the proteid is dissolved. What is the effect 

 of cold on the action? of high temperatures? of excess of 

 acid? of excess of alkali? Test Tube 1 with litmus. What 

 is its reaction? 



(Pancreatin contains an enzyme called trypsin, which, 

 like pepsin, acts on proteid and converts it into peptone.) 

 From the above experiments, does trypsin require an acid 

 medium? (Pepsin will not act in the intestine because the 

 contents of the intestine are alkaline.) 



B. Action of the Starch Enzyme of Pancreatin (Amylopsin). 

 Place a little pancreatin solution in three test tubes and 

 label Tubes 1, 2, and 3. 



Tube 1. Test with Fehling's solution. Does the pan- 

 creatin solution contain grape sugar? 



Tubes 2 and 3. Add to the second and third tubes a little 

 dilute starch paste. Test with litmus. Is the solution acid 

 or alkaline? To Tube 3 add enough hydrochloric acid to 

 give a distinct acid reaction with litmus. Keep both tubes 

 at 36 C. for twenty-four hours. Then test with Fehling's 

 solution. Record results. Are they the same in both 

 tubes? 



(Amylopsin will act only in a basic medium.) 



C. Emulsion and Action of Fat Enzyme (Steapsin). To 

 pancreatin solution add the 1.5% sodium carbonate solu- 

 tion as directed in Ex. XXXV, C. Shake some olive oil in 



