PANCREATIC DIGESTION. 149 



and to the contents of the other tube add 3 c.c. of water or of boiled 

 neutral pancreatic extract. Keep the tubes at 40 C. and note 

 any changes which may occur. What is the result and how do 

 you explain it? 



2. Ethyl Butyrate Test. Into each of two test-tubes introduce 

 4 c.c. of water, 2 c.c. of ethyl butyrate, C 3 H 7 COO C 2 H 5 , and 

 a small amount of litmus powder. To the contents of one tube 

 add 4 c.c. of neutral pancreatic extract and to the contents of the 

 other tube add 4 c.c. of water or boiled neutral pancreatic extract. 

 Keep the tubes at 40 C. and observe any changes which may 

 occur. What is the result and how do you explain it? Write the 

 equation for the reaction which has taken place. 



EXPERIMENTS ON PANCREATIC RENNIN. 



Prepare four test-tubes as follows : 



(a) Five c.c. of milk -f- 10 drops of neutral pancreatic extract. 



(b) Five c.c. of milk + 20 drops of neutral pancreatic extract. 



(c) Five c.c. of milk + 10 drops of alkaline pancreatic extract. 



(d) Five c.c. of milk -f- 20 drops of alkaline pancreatic extract. 

 Place the tubes at 6o-65 C. for a half hour without shaking. 



Note the formation of a clot. 1 How does the action of pancreatic 

 rennin compare with the action of the gastric rennin? 



1 This reaction will not always succeed, owing to conditions which are 

 not well understood. 



