DIGESTION OF FOOD. 



305 



Pancreatic Juice. — This fluid is found to vary a good deal 

 quantitatively, according as it is obtained from a temporary 

 (freshly made) or permanent fistula — a fact which emphasizes 

 the necessity for caution in drawing conclusions about the 

 digestive juices as obtained by our present methods. 



The freshest juice obtainable through a recent fistulous 

 opening in the pancreatic duct is clear, colorless, viscid, alka- 

 line in reaction, and with a very variable quantity of solids 

 (two to ten per cent), less than one per cent being inorganic 

 matter. 



Among the organic constituents the principal are albumin, 

 alkaH-albumin, peptone, leucin, tyrosin, fats, and soaps in smaJl 

 amount. The alkalinity of the juice is owing chiefly to sodium 



FiQ. 247.— Crystals of leucin (Fanke). 



Pig. 248.— Crystals of tyrosin (Funke). 



carbonates, which seem to be associated with some proteid 

 body. There is little doubt that leucin, tyrosin, and peptone 

 arise from digestion of the proteids of the juice by its own 

 action. 



Experimental— If the pancreatic gland be mostly freed from 

 adhering fat, cut up, and washed so as to get rid of blood; 

 then minced as fine as possible, and allowed to stand in one-per- 

 cent sodium-carbonate solution at a temperature of 40° C, the 

 following results may be noted : 1. After a variable time the 

 reaction inay change to acid, owing to free fatty acid from 

 the decomposition (digestion) of neutral fats. 2. Alkali-albu- 

 min, or a body closely resembling it, may be detected and sep- 

 arated by neutralization. 3. Peptone may be detected by the 



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