204 PHYSIOLOGICAL CHEMISTRY. 



than the other pancreas-enzymes, and it has indeed been questioned 

 whether or not the decomposition of the neutral fats in the intestine 

 may not be effected through lower organisms. According to the 

 investigations of NENCKI, it seems that the pancreas actually con- 

 tains an enzyme which decomposes fats. This enzyme, which is 

 still little known, appears to be very sensitive to acids, and it is 

 often absent in acid glands not perfectly fresh. If a watery in- 

 fusion of the gland prepared cold be treated with calcined magnesia, 

 then the enzyme in question will, according to DANILEWSKI, be 

 retained by the magnesia precipitate. 



The fatty acids which are split off by the action of the pan- 

 creatic juice combine in the intestine with the alkalies, forming 

 soaps which have a strong emulsifying action on the fats, and 

 thus the pancreatic juice becomes of great importance in the emul- 

 gtification and the absorption of the fats. 



Trypsin. The action of the pancreatic juice in digesting pro- 

 teids was first observed by BERNARD, but first proved by CORVISART. 

 It depends upon a special enzyme called by KUHNE trypsin. 

 Strictly speaking, this enzyme does not occur in the gland itself. 

 In the gland, more probably, a zymogen occurs from which the 

 enzyme is split off or formed by the secretion, also by the action of 

 water, acids, alcohol, and other substances. According to ALBER- 

 TONI, this zymogen is found in the gland in the last third of the 

 intra-uterine life. 



The purest trypsin thus far prepared, isolated by KUHNE, is 

 soluble in water but insoluble in alcohol or glycerin. The less pure 

 enzyme, on the contrary, is soluble in glycerin. If the solution of 

 the enzyme in water is heated to the boiling point with the addi- 

 tion of a little acid, it decomposes into coagulated albumin and 

 peptone (KiJHNE). It is destroyed by gastric juice. Like other 

 enzymes, trypsin is characterized by its physiological action. This 

 action consists in its power of dissolving albumin, and especially 

 easily fibrin, in alkaline, neutral, and even in faintly acid-reacting 

 solutions. 



The production of pure trypsin has been tried by various ex- 

 perimenters, DANILEWSKI, HUFNER, KUHNE, LOEW, and others. 

 The purest seems to have been prepared according to the rather com- 

 plicated method of KUHNE. In studying the action of trypsin a 



