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 



Monobasic acids 

 of fatty series 



Leucine (aminoisobutylacetic acid) 



Isoleucine (aminocaproic acid) .... 



Aspartic acid . . .1 .-.., . . , 



Dibasic acids 

 Glutamic acid ....... J 



Phenylalanine ....... \ Benzene (aromatio) 



Tyrosine (oxyphenylalanine) / derivatives 



Proline (pyrrolidine carboxylic acid) ^ 



Oxyproline (oxypyrrolidine carboxylic acid) . . I Heterocyclio 



compounds 

 Tryptophane (indolaminopropionic acid) 



DlAMINO-ACLDS AND THEIR COMPOUNDS 



Lysine (diaminocaproic acid) .... n i 



Arginine (guanidinaminovalerianio acid) hexone bases ' 



Histidine (iminazolalanine) . 



* Diaminotrioxydodecoic acid ' . . . derived from a 12-carbon acid 



( Sulphur-containing 

 Cystme (derived from ammothiopropionic 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. 



