96 THE PANCREATIC JUICE. 



210. Prepare an artificial pancreatic juice by ex- 

 tracting a finely-chopped pancreatic gland of a hog or ox 

 with lukewarm water. It is better to wait an hour or two 

 after killing the animal, in order to allow of the forma- 

 tion of the active ferment, or to use 0.2 per cent, salicylic 

 acid solution for the same purpose; this also prevents 

 putrefaction. Chloroform water gives an extract with 

 marked proteolytic properties: alcohol gives a strongly 

 lipolytic and amylolytic solution. Filter the extract 

 through cloth and add to the filtrate a little chloroform or 

 thymol to prevent putrefaction, which easily occurs with- 

 out an antiseptic. Place in the liquid 10 to 15 grammes 

 of fibrin, make slightly alkaline with sodium carbonate, 

 and allow it to stand at about body-temperature until it 

 has all dissolved. The products obtained will depend upon 

 the time. If the digestion is stopped too soon they will be 

 largely albumoses and peptones, but later there will be 

 more of the leucin and tyrosin. The best results will be 

 obtained by digesting for several hours, or as much as a 

 day. 



When digestion is well advanced test a small portion 

 of the liquid by adding bromin-water drop by drop. A 

 reddish violet precipitate shows the presence of tryptophan, 

 which only appears after the peptone molecule has com- 

 menced to break down. It is destroyed by an excess of the 

 reagent. 



Filter a second portion and cautiously add to the fil- 

 trate acetic acid until the reaction is neutral. Globulin 

 or alkali albumin is precipitated. This may be coagulated 

 by boiling and removed by filtration, then the filtrate tested 

 for the other products. To this filtrate add a few drops 

 of sulphuric acid, then crystals of ammonium sulphate 

 until it is saturated. The precipitate of albumoses can be 



