DIGESTION AND THE DIGESTIVE AGENTS. 341 



tiniest globules the absorbing cells of the intestine are able 

 to manage them properly. 



In the emulsion of these fats the soap formed in the in- 

 testine seems to figure directly. Probably the tiny little 

 droplets of fat are surrounded by thin envelopes of soap and 

 so prevented from reuniting. That soap is pre-eminently 

 fitted in making an emulsion is evident as soon as we think 

 of soap-suds and lather. We have, therefore, to picture to 

 ourselves the way in which the fat is acted upon about as 

 follows: The liberated fats of the stomach reach the in- 

 testine, meet some of the steapsin ferment, and are then 

 partly split into a fatty acid and glycerine. The fatty acid 

 at once unites with some alkaline ingredient of the pan- 

 creatic juice or bile and soap is formed. This soap by 

 means of the peristaltic motions of the intestine is shaken 

 up with the remaining fats and emulsifies them, so getting 

 them ready for absorption. That some of the fats in the 

 form of soap, finally reach the blood, is probable, but the 

 physiological value of this soap is in its emulsifying action 

 upon the remaining and larger portion of the fats. 



Summary. What, then, is the final state of things 

 after the process of pancreatic digestion has continued for 

 several hours? 



Of course while the pancreatic digestion has been going 

 on the bile has been poured into the intestine and has pro- 

 duced some effects, and the intestinal juice has also been 

 acting. But leaving this out of consideration for the pres- 

 ent the final state of things is about as follows : 



First: All the proteids which the stomach has left un- 

 touched and all those proteids which the stomach has 

 only partially changed into peptones, have been completely 

 changed into peptones by the trypsin. 



Second: Any albuminoids that may have escaped di- 

 gestion in the stomach are dissolved and the gelatine ex- 

 tracted. 



