470 FATE OF BODY-FOREIGN SUBSTANCES 



The observation in E. Friedmann's laboratory 43 of rup- 

 ture of the naphthalin nucleus when naphthalanin and 

 naphthyl-racemic acid pass into benzoic acid may be noted 

 here, 



-COOH. 



It is known, too, that tyrosin and probably phenylalanin 

 undergo advanced disintegration in the normal body ; but on 

 the other hand an individual with alcaptonuria (v. Vol. I of 

 this series, p. 47, et seq., Chemistry of the Tissues) brings 

 this nucleus in hydroxylized form in the shape of homogen- 

 tisic acid, TTA | ] to the surface of metabolism, 

 tujk J CH2 COOH * 



The fact that homogentisic acid and its mother substances in 

 the body may undergo transition into aceto-acetic acid, or 

 into -oxybutyric acid, 46 may perhaps be interpreted as indi- 

 cating that homogentisic acid is split off as in the schema, 47 



C.OH 



HC 



CO CHr-COOH 

 CH, ; 



yet, according to what has been previously said in reference 

 to the formation of acetone bodies, it would appear at least 

 quite as plausible that homogentisic acid would break down 

 into a bicarbon complex, and /?-oxybutyric acid be formed by 

 way of acetaldehyde and aldol synthesis. 



45 F, Kikkoji (First Med. Clinic, Berlin), Biochem. Zeitschr., 35, 57, 1911. 



48 G. Embden, H. Salomon and F. Schmidt (Frankfurt a. M.), Hofmeister's 

 Beitr., 8, 129, 1906; G. Embden and H. Engel (Frankfurt a. M.), Hof- 

 meister's Beitr., 11, 323, 1908; J. Bar and L. Blum, Arch. f. exper. Pathol., 

 56, 92, 1907. 



T. Kikkoji, I.e., p. 63. 



