PANCREATIC DIGESTION 1 89 



absorbed. Bloor further claims 1 that in the absorption of fats there is 

 a tendency toward the formation of a uniform chyle fat, presumably the 

 characteristic body fat of the animal. 



Pancreatic lipase is very unstable and is easily rendered inert by the 

 action of acid. For this reason it is not possible to prepare an extract 

 having a satisfactory fat-splitting power from a pancreas which has 

 been removed from the organism for a sufficiently long time to have 

 become acid in reaction. 



The fourth enzyme of the pancreatic juice is called pancreatic rennin. 

 It is a milk-coagulating enzyme whose action is very similar to that 

 of the gastric rennin found in the gastric juice. It is supposed to show 

 its greatest activity at a temperature varying from 60 to 65C. 



PREPARATION OF AN ARTIFICIAL PANCREATIC JUICE 2 



After removing the fat from the pancreas of a pig or sheep, finely divide the 

 organ by means of scissors and grind it in a mortar. If convenient, the use of an 

 ordinary meat chopper is a very satisfactory means of preparing the pancreas. 



When finely divided as above the pancreas should be placed in a 500 c.c. 

 flask, about 150 c.c. of 30 per cent alcohol added and the flask and contents shaken 

 frequently for 24 hours. (What is the reaction of this alcoholic extract at the end 

 of this period, and why?) Strain the alcoholic extract through cheese cloth, 

 filter, nearly neutralize with potassium hydroxide solution and then exactly 

 neutralize it with 0.5 per cent sodium carbonate. 



Products of Tryptic Digestion 



Take about 200 grams of lean beef which has been freed from fat and finely 

 ground and place it in a large-sized beaker. Introduce equal volumes of the pan- 

 creatic extract prepared as above and 0.5 per cent sodium carbonate, add 5 c.c. 

 of an alcoholic solution of thymol to prevent putrefaction, and place the beaker in 

 an incubator at 4OC. Stir the contents of the beaker frequently and add more 

 thymol if it becomes necessary. Allow digestion to proceed for from two to five 

 days and then separate the products formed as follows: Strain off the undis- 

 solved residue through cheese cloth, nearly neutralize the solution with dilute 

 hydrochloric acid and then exactly neutralize it with 0.2 per cent hydrochloric acid. 

 A precipitate at this point would indicate alkali metaprotein (alkali albuminate). 

 Filter off any precipitate and divide the filtrate into two parts, a one -fourth and a 

 three-fourth portion. 



Transfer the one-fourth portion to an evaporating dish and make the sepa- 

 ration of proteoses and peptones as well as the final tests upon these bodies 

 according to the directions given on page 120. 



Place about 5 c.c. of the three-fourth portion in a test-tube and add about 

 i c.c. of bromine water. A violet coloration 3 indicates the presence of trypto- 



1 Bloor: Jour. BioL Chem., 16, 517, 1914. 



2 For other methods of preparation see Karl Mays: Zeitschrift fur physiologische Chemie, 

 38, 428, 1903. 



3 Kurajeff : Zeit. physiol. Chem., 36. 501, 1898-99. 



