DIGESTION. 201 



Inasmuch as during pancreatic digestion antipeptone is present 

 as well as leucin and tyrosin, it is believed by some investigators that 

 both antipeptone and hemipeptone are formed from the deutero- 

 albumose, the latter speedily undergoing decomposition. This view 

 is illustrated in the following scheme : 



Proteid 



Alkali-albumin 



[ 

 Deutero-proteose or deutero-albumose 



Anti-peptone Hemipeptone 



Leucin Tyrosin Aspartic acid, etc. 



When the proteids which have escaped digestion in the stomach 

 pass into the small intestine and mingle with the pancreatic juice, 

 they are doubtless digested in the course of the intestinal canal, 

 passing through the stages just described. As leucin and tyrosin are 

 found in the intestine during digestion, it is probable that a portion 

 of the peptone undergoes decomposition into these bodies; but as 

 to the extent to which this takes place or in how far it is a necessary 

 process under normal conditions, nothing definite can be said. It is 

 probable that it takes place when there is an excess of proteid food 

 or when for any reason digestion is prolonged or absorption is delayed. 



3. On fat. If pancreatic juice be added to a perfectly neutral 

 fat -olein, palmitin, or stearin and kept at a temperature of about 

 100 F. (38 C.), it will at the end of an hour or two be partially de- 

 composed into glycerin and the particular fatty acid indicated by 

 the name of the fat used e. g., oleic, palmitic, stearic. The oil will 

 then exhibit an acid reaction. The reaction is represented in the 

 following formula: 



C 3 H 5 (C 18 H 33 2 )3 + 3 H 2 - (C 18 H 34 2 ) 3 + C 3 H 5 (HO) S 

 Triolein. Water. Oleic Acid. Glycerin. 



If to this acidified oil there be added an alkali, e. g., potassium or 

 sodium carbonate, the latter will at once combine with the fatty acid 

 to form a salt known as a soap. The reaction is expressed in the 

 following equation : 



Sodium Carbonate. Oleic Acid. Sodium Oleate. Carbonic Acid. 



Na 2 C0 3 + C 18 H 34 2 = Na 2 OC 18 H 32 2 + H 2 CO 3 



Coincident with the formation of the soap the remaining neutral oil 

 undergoes division into drops of microscopic size, which float in the 

 soap solution, forming what has been termed an emulsion, which is 

 white and creamy in appearance. The action of the pancreatic juice 



