CONTENTS XXI 



VII. The IMelabolisni of Branched-Chain Acids, Hydroxy and Keto 

 Acids, Dicarboxylic Acids, Tricarboxylic Acids, Fatty Acid Amides, 

 Fatty Acid Aldehydes, and Hydrocarbons (continued) 



a. Functions of the Dicarboxylic Acids 305 



(a) The Role of Dicarboxylic Acids in the Tricarboxylic Acid 



Cycle 305 



(b) The Role of Dicarboxylic Acids as Intermediary Products 



in Fatty Acid Oxidation 306 



b. The Occurrence and Metabolism of Dicarboxylic Acids 307 



(a) Introduction 307 



(b) Succinic Acid 308 



(c) Dicarboxylic Acids Having More Than Four Carbons. . . . 310 

 (2) Tricarboxylic Acids 314 



4. Fatty Acid Amides 315 



5. Fatty Aldehydes 317 



6. Hydrocarbons 319 



(1) Aliphatic Hydrocarbons 319 



a. Paraffin Hydrocarbons and Related Compounds 319 



(a) The Presence of Paraffin Hydrocarbons in Plant and Insect 



Waxes 319 



(b) The Presence of Comi)ounds Related to Hydrocarbons in 



Plant and Insect Waxes 321 



a'. Primary Alcohols 321 



b'. Secondary Alcohols 322 



c'. Ketones 322 



b. Unsaturated Hydrocarbons in Plants and Animals 322 



(a) Squalene 322 



(b) Unsaturated Hj^drocarbons Other Than Squalene 325 



c. The Metabolism of Aliphatic Hj'drocarbons and of Related 



Compounds 325 



(2) Aromatic Hydrocarbons 328 



a. Benzene and Related Compounds 328 



(a) Benzene 328 



a'. The Elimination of Unchanged Benzene 328 



b'. Oxidation of Benzene to Phenol 329 



c'. Oxidation of Benzene to Di- and Trihydroxyphenols. 330 



d'. Conjugation of Phenols 332 



a". Conjugation with Sulfuric Acid 333 



b". Conjugation with Olucuronic Acid 333 



e'. Oxidation of Benzene to Muconic Acid 334 



f '. Transformation of Benzene to Phenylmercapturic Acid 339 



g'. Resume of the Metabolism of Benzene 340 



(b) Toluene and Other Methyl-Substituted Benzenes 341 



(c) Higher Homologues of Benzene 343 



a'. Ethylbenzene 343 



b'. M-Alkylbenzenes 344 



c'. Iso-Alkylbenzenes 344 



