THE PHYSIOLOGY OF DIGESTION 705 



Asparticacid . . )D ibasic acids 



Glutamic acid . . . . ) 



Phenylalanine ....... \Benzene (aromatic) deriva- 



Tyrosine (oxyphenylalanine) . . . . . ) tives 



Proline (pyrrolidine carboxylic acid) . \ 



Oxyproline (oxypyrrolidine carboxylic acid) . . * Heterocyclic compounds 



Tryptophane (indolaminopropionic acid) . . 



DlAMINO-ACEDS AND THEIR COMPOUNDS 



Lysine (diaminocaproic acid) . . 1 



Arginine (guanidinaminovalerianic acid) . . . hThe ' hexone bases ' 



Histidine (iminazolalanine) . . . . J 



fDerived from a 12-carbon 

 Diaminotnoxydodecoic acid ... . -j .^ 



Cystine (derived from aminolhiopropionic acid) . . Sulphur- containing body 



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. 



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