41 



PANCREATIC DIGESTION 



137. The pancreatic secretion is a clear thick alkaline 

 fluid, rich in solids, and possesses very active enzyme proper- 

 ties. It contains at least three distinct enzymes, besides albu- 

 min, leucin, fats, soaps and salts. These solid constituents 

 make up about 10% of the secretion. The enzymes occur in 

 the gland in the form of inactive zymogens, but are changed 

 to the active form a few hours after death or by the action 

 of water or acids. The reaction of the juice is alkaline from 

 the presence of sodium carbonate. The extract made from the 

 gland by means of warm water may be acid in reaction from 

 the presence of sarco-lactic acid, especially if the gland is 

 extracted some time after death. 



The ingestion of food stimulates the flow of the pancreatic 

 fluid. There is, therefore, no secretion during starvation and 

 it is intermittent in carnivorous animals where some time 

 elapses between meals. On the other hand secretion is going 

 on almost continually in herbivorous animals because digestion 

 is uninterruptedly taking place. 



The enzymes found in the pancreatic juice are : trypsin 

 which digests proteidsin an alkaline medium, amylopsin which 

 digests starch similarly to ptyalin, steapsin which splits up 

 fats into glycerine and fatty acids, and finally there is some 

 evidence of a milk-curdling enzyme, although the latter is not 

 universally accepted. 



A pancreatic extract for digestive purposes with trypsin 

 and amylopsin may be made by running the gland through a 

 food chopper, or triturating it to a pulp in a mortar and add^ 

 ing 1 cc. of 1% acetic acid for each gram of the pancreas, to 

 liberate the enzyme from the zymogen granules. Then add 

 10 cc. of chloroform water for each gram of the pancreas to 

 extract the enzymes and at the same time, on account of its 

 antiseptic properties, to prevent putrefaction. For use, 2 cc. 

 of this extract may be added to 8 cc. of 1% sodium carbonate, 

 or equal volumes of the two may be employed. 



Commercial pancreatin 5 grams dissolved in 200 cc. of 

 1 '^c sodium carbonate will also serve for experimental purposes. 



