464 FATE OF BODY-FOREIGN SUBSTANCES 



to trace the fate of a few body-foreign substances in the 

 intermediate metabolism. 32 



Decomposition of Fatty Acids and Aliphatic Sidechains. 

 In taking up first the fatty acids and aliphatic sidechains 

 we keep in direct connection with the information gained 

 in the course of the last few lectures as to the catabolism of 

 fats and the origin of the acetone bodies. It was pointed out 

 that the investigations of Knoop and Embden particularly 

 have led to the recognition that in the disintegration of the 

 normal fatty acids in the animal body /^-oxidation plays 

 an important part, and that as a mode of oxidation we can 

 picture: E.CH 2 .CH 2 .COOH >E.CH(OH).CH 2 .COOH *- 

 E.CO.CH 2 .COOH > E.COOH ; in which a normal fatty acid 

 passes first into a -oxyacid by /?-hydroxylation, and this then 

 through the corresponding /?-ketonic acid into an acid with 

 two less carbon atoms. 



A long series of careful studies conducted in the past few 

 years, requiring much chemical scientific knowledge and 

 skill, especially by E. Friedmann, F. Knoop, H. D. Dakin and 



0. Neubauer, 33 have been devoted to tracing out the fate of 

 many phenyl, halogenphenyl, furfuryl and similar substitu- 

 tions in fatty acids, oxyacids, ketonic acids and aminoacids in 

 the course of metabolism. These studies, the details of 

 which cannot be entered into here, have shown that the above 

 mentioned simple schema of /^-oxidation cannot be accepted 

 as of general applicability, and that oxidation of fatty acids 



82 Literature upon the Excretion of Body-foreign Organic Substances : A. 

 Heffter, Ergebn. d. Physiol., 4, 184-306, 1905. 



88 F. Knoop, Der Abbau aromatischer Fettsauren im Tierkorper, Freiburg 



1. B., 1904; Hofmeister's Beitr., 11, 1908, and later works; E. Friedmann, 

 Hofmeister's Beitr., 11, 151, 1908; E. Friedmann and C. Maase, Bfochem. 

 Zeitschr., 27, 97, 113, 1910; E. Friedmann, ibid., 27, 119, 1910; 35, 40, 1911; 

 Med. Klinik, 1909, Nos. 36 and 37, and 1911, No. 28; T. Sasaki (E. Friedmann's 

 Lab.), ibid., 25, 272, 1910; H. D. Dakin (New York), Jour, of Biol. Chem., 

 4-6, 1908-09; 8, 35, 1910; 9, 123,1911; O. Neubauer, with W. Gross, H. 

 Fischer, K. Fromherz, Zeitschr. f. physiol. Chem., 67, 219, 230, 1910; 70, 326, 

 1911; Literature upon the Catabolism of Fatty Acids and Aliphatic Side 

 Chains: 0. Forges, Ergebn. d. Physiol., 10, 1-46, 1910; C. Oppenheimer and 

 Pincussohn, ibid., 4', 699-700, 706-709, 1911. 



