PRODUCTS OF PANCREATIC DIGESTION. I 87 



THE ACTION OF THE PANCREAS ON FATS. 



In the general discussion of the subject of enzymes it was 

 shown that a certain product of the pancreas called steapsin 

 or lipase is active in splitting neutral fats into glycerol and 

 acid. This is a true change by hydrolysis and in effect is 

 similar to the splitting by water alone at an elevated tempera- 

 ture. In the pancreas the reaction may not be complete, but 

 may extend only to the separation of one-third of the acid as 

 illustrated by this equation for stearin : 



r 

 ^ 

 L 



CuH0, r OH 



GH.J C 18 H 35 

 I G.HO a 



This amount of liberated acid combining with the sodium 

 carbonate of the intestinal juices produces a soap which in 

 turn aids in the emulsification of the rest of the fat and thus 

 prepares for its passage through the intestinal walls. On the 

 other hand, certain writers maintain that the fat must be essen- 

 tially all split before absorption is possible. The fatty acid 

 and glycerol pass through the intestinal walls directly and 

 recombine. The change in this case would follow through 

 the typical equation : 



GH.(C M H0,). + 3H 2 = C 3 H 5 (OH) 3 



The behavior of the pancreas may be shown by experiment, 

 but for this purpose it is much better to use the fresh pancreas 

 than to depend on extracts. The lipase seems to be soluble 

 in glycerol to some extent, but unless the fresh gland is em- 

 ployed for the extraction the result may be unsatisfactory. 

 These points may be tested by the student : 



Ex. Rub up a part of a pancreas with some fine, clean sand in a mor- 

 tar to bring it into the condition of a creamy paste. Add some water, 

 mix thoroughly, and use this for the tests. Next melt some butter to 

 allow the curd and salt to settle. Collect the clear butter fat. Mix a 

 few grams of the fat with an equal volume of the pancreas paste, add 

 some water and a few drops of chloroform as preservative. Keep the 

 mixture at a temperature of 40 through a period of several hours or over 

 night, and observe that it gradually becomes acid through the liberation 



