THE PHYSIOLOGY OF DIGESTION 739 



(3) Proteins. Here we have a great variety of mono- and diamino- 

 acids, which may be enumerated as follows : 



MONO-AMINO-ACIDS 



Glycine (aminoacetic acid) .... 



Alanine (aminopropionio acid) 



Serine or oxyalanine (oxyaminopropionic acid) 



Aminovalerianic acid ..... 



Leucine (aminoisobutylacetic acid) 



Isoleucine (aminocaproic acid) 



Aspartic acid ...... 



Glutamic acid ...... 



Phenylalanine ...... 



Tyrosine (oxypbenylalanine) 

 Proline (pyrrolidine carboxylic acid) 

 Oxyproline (oxypyrrolidine carboxylic acid) . 



Tryptophane (indolaminopropionic acid) 



Monobasic acids 

 of fatty series 



Dibasic acids 



) Benzene (aromatic) 

 J derivatives 



Heterocyclic 



compounds 



f 



Ihe 

 ' hexone bases 



DlAMTNO-ACTDS AND THEIR COMPOUNDS 



Lysine (diaminocaproic acid) .... 



Arginine (guanidinaminovalerianic acid) 



Histidine (iminazolalanine) .... 



' Diaminotrioxydodecoic acid ' derived from a 12-carbon acid 



f Sulphur-containing 

 I body 



Cystine (derived from aminothiopropionic acid) 



Those constituents of the food which undergo no oxidation in 

 the body, such as the water and salts, are practically unchanged 

 in the alimentary canal, and are absorbed in their original form into 

 the blood. 



