The Liver and Pancreas. 171 



1. Peptic digestion is an acid one; pancreatic is essen- 

 tially an alkaline one. 



2. If fibrin be digested by trypsin, during the action of 

 the ferment the fibrin does not swell up as in peptic diges- 

 tion. Further, the fibrin is eroded by the action of 

 trypsin, rather than dissolved as in peptic digestion. 



3. The outcome of pancreatic digestion is an alkali- 

 albumin, and not an acid one, as in the stomach ; and the 

 proteids in the case of pancreatic digestion ,undergo a 

 change not only into peptones, but a portion of them is 

 further converted into leucin, tyrosin, and other sub- 

 stances. The production of indol, phenol, and skatol in 

 pancreatic proteid digestion cannot be regarded as due to 

 the pancreas, but to the presence of micro-organisms and 

 consequent putrefaction. 



By these reactions it is easy to distinguish between a 

 peptic and pancreatic digestion ; it is very remarkable that 

 peptone products can be obtained through the action of 

 two such apparently opposite secretions as gastric and 

 pancreatic juice. 



The action on starchy food is to convert it into sugar, 

 and this it is capable of doing with extreme rapidity; 

 15£ grains of pancreatic juice can convert in half an hour 

 71 grains of starch into sugar ; the form of sugar produced 

 is maltose, with a little glucose ; the fluid has no action on 

 cane-sugar, but on starch it acts on the unboiled as well as 

 on the boiled variety. 



On fats the action is very marked : the fats are first con- 

 verted into an emulsion, by which means the particles of 

 oil are finely divided; in the next stage the fat itself is 

 split up into its constituents, viz., fatty acids and glycerin, 

 and th3 former in the presence of an alkali forms soaps. 

 The alkaline salts of the pancreatic juice assist in this 

 action. 



The pancreatic juice of the horse emulsifies less com- 

 pletely than that of other animals. 



The presence of alkaline salts, especially carbonate of 

 soda, assists in the emulsifying of fat. 



