PANCREATIC DIGESTION. 1 47 



EXPERIMENTS ON PANCREATIC AMYLASE. 



1. The Most Favorable Reaction. Prepare seven tubes as 

 follows : 



(a) One c.c. of neutral pancreatic extract + I c - c - of starch paste 

 + 2 c.c. of water. 



(b) One c.c. of neutral pancreatic extract + i c.c. of starch paste 

 + 2 c.c. of i per cent sodium carbonate. 



(<:) One c.c. of neutral pancreatic extract -f- i c.c. of starch paste 

 + 2 c.c. of 0.5 per cent sodium carbonate. 



( d) One c.c. of neutral pancreatic extract -f- i c.c. of starch paste 

 + 2 c.c. of 0.2 per cent hydrochloric acid. 



(<?) One c.c. of neutral pancreatic extract + i c.c. of starch paste 

 + 2 c.c. of 0.2 per cent combined hydrochloric acid. 



(/) One c.c. of neutral pancreatic extract + i c.c. of starch paste 

 + 2 c.c. of 0.4 per cent boric acid. 



(g) One c.c. of neutral pancreatic extract -f- i c.c. of starch paste 

 -f- 2 c.c. of 0.4 per cent acetic acid. 



Shake each tube thoroughly 'and place them on the water-bath 

 at 40 C. At the end of a half-hour divide the contents of each 

 tube into two parts and test one part by the iodine test and the 

 other part by Fehling's test. Where do you find the most satisfac- 

 tory digestion? How do the results here compare with those ob- 

 tained from the similar series under Trypsin, page 145. 



2. The Most Favorable Temperature. (For this and the fol- 

 lowing series of experiments upon pancreatic amylase use the 

 neutral extract plus an equal volume of 0.5 per cent sodium car- 

 bonate.) In each of four tubes place 2-3 c.c. of alkaline pan- 

 creatic extract. Immerse one tube in cold water from the faucet, 

 keep a second at room temperature and place a third on the water- 

 bath at 40 C. Boil the contents of the fourth for a few moments, 

 then cool and also keep it at 40 C. Into each tube introduce 2-3 

 c.c. of starch paste and note the progress of digestion. At the end 

 of one-half hour divide the contents of each tube into two parts and 

 test one part by the iodine test and the other part by Fehling's 

 test. In which tube do you find the most satisfactory digestion? 

 How does this result compare with the result obtained in the sim- 

 ilar series of experiments under Trypsin (see page 146) ? 



3. Influence of Metallic Salts, etc. Prepare a series of tubes 

 and into each place 3 volumes of water, 3 volumes of alkaline pan- 

 creatic extract, i volume of one of the chemicals listed in Experi- 

 ment 1 8 under Salivary Digestion, page 59, and 3 volumes of 



