EXAMINATION OF THE PANCREAS. 77' 



ground with ether, again filtered and pressed, dried in the air by 

 allowing the ether to evaporate; again ground and sifted through- 

 wire gauze, using only the powder that passes through the sieve. In- 

 stead of using the powder directly we may also digest it for a day at 

 40 with chloroform-water (2.5 g. : 100 cc.), to which some drops of 

 sodium carbonate solution have been added, and use the filtrate for 

 the experiment. The action is usually somewhat weaker; in many 

 cases, however, such a solution is to be preferred. Kuhne prepares, 

 an extract from the pancreas-powder by digesting for three or four 

 hours one part of the powder with five to ten parts of a salicylic acid 

 solution (0.1 per cent.), and then filtering. 



The mixture of fibrin, pancreas-powder, and chloroform-water 

 must have a distinctly alkaline reaction. When fresh fibrin is used 

 the addition of 5 cc. of a concentrated sodium carbonate solution is- 

 sufficient. When coagulated fibrin which has been previously treated 

 with dilute hydrochloric acid is used it may easily retain some of the 

 acid, and in this case the 5 cc. of sodium carbonate is insufficient. We 

 must then repeatedly add sodium carbonate solution, until even after 

 standing for a considerable time the mixture has a distinctly alkaline 

 reaction. 



The mixture is digested at 40 in a glass-stoppered bottle- 

 for forty-eight to seventy-two hours and should be repeatedly 

 shaken thoroughly during the digestion. After the digestion, 

 make the contents of the bottle quite faintly acid with acetic 

 acid, heat to boiling in an enamelled-iron dish or tinned ves- 

 sel, and filter. 



1. To a small portion of this filtrate (A) add, drop by drop,, 

 and with constant shaking, some bromine- water: the fluid 

 takes on a violet color : try ptophan reaction. The rest of the- 

 filtrate is evaporated to a thin sirup (about 100 cc.) and let 

 stand for some days in a cool place. A considerable quantity 

 of white granular crystals of tyrosine separates (B) . Decant 

 through muslin, put the tyrosine into a dish or beaker and 

 wash it quickly a few times by decantation, then put it into 

 a flask and heat with water to which a little ammonia has 

 been added, and filter. The hot filtrate is evaporated on the 



