n CHANGES DURING METABOLISM 113 



We may, secondly, obtain as the result of some pathological state 

 certain intermediate products of metabolism. Although we cannot 

 with certainty exclude the possibility that * the car was not running 

 previously on wrong lines,' it is generally believed that we are dealing 

 with substances which arose normally, but the oxidation of which has 

 somehow been interfered with, and that for this reason the substances 

 leave the kidney in an unoxidised condition. This view is upheld in 

 the case of alcaptonuria by Mayer, 1 Mittelbach, 2 Garrod, 3 Abderhalden 

 and Falta; 4 Garrod describes the condition as a 'chemical abnor- 

 mality' one might add, as an abnormality due to arrest of 

 development (Cohnheim). 



The occurrence of mono -amino- acids in the urine during normal 

 and pathological conditions has been studied by Abderhalden, 5 Abder- 

 halden and Bergell, 6 Ignatowski, 7 and Abderhalden and Barker, 8 and 

 Erben. 9 For methods of studying the diamines of the urine fsee the 

 paper by Loewy and Neuberg. 10 



Cystin has been observed in the urin 11 and also in the tissues 

 in a case of cystinuria. 12 Other substances occurring in the urine 

 are cadaverin and putrescin, 13 which frequently accompany cystin, 

 and the peculiar substances found in alcaptonuria. The chief sub- 

 stance seen in cases of alcaptonuria is, according to Baumann and 

 Wolkow u and Huppert, 15 homogentisinic acid or dioxyphenyl-acetic 

 acid, in addition to which Kirk 16 observed also uroleucic acid or 

 dioxyphenyl-lactic acid. The latter is derived from tyrosin, and, as 

 Falta and Langstein 17 have found, also from phenylalanin. The 



1 E. Mayer, Deutsch. Arch. f. Min. Med. 70. 443 (1901). 



2 F. Mittelbach, ibid. 71. 50 (1901). 



3 A. E. Garrod, The Lancet, 1901, II. 1484 ; 1902, II. 1616. 



4 E. Abderhalden and W. Falta, Zeitschr. f. physiol. Chem. 39. 143 (1903) ; W. 

 Falta, Baseler Naturf. Ges. 15. Heft 2 (1903). 



5 E. Abderhalden, Zeitschr. f. physiol. Chem. 38. 557 (1903). 



6 E. Abderhalden and Peter Bergell, ibid. 39. 9 and 464 (1903). 



7 Alexander Ignatowski, ibid. 42. 371 (1904). 



8 E. Abderhalden and Lewellys. F. Barker, ibid. 42. 524 (1904). 



9 Franz Erben, ibid. 43. 320 (1904). 



10 A. Loewy and C. Neuberg, ibid. 43. 355 (1904). 



11 E. Baumann and L. v. Udranszky, ibid. 13. 562 (1889), 15. 77 (1890). Com- 

 pare with p. 56 of this book. 



12 E. Abderhalden, ibid. 38. 557 (1903). 



13 E. Baumann and v. Udranszky, ibid. 13. 562 (1889), 15. 77 (1891). 



14 M. Wolkow and E. Baumann, ibid. 15. 228 (1891). 



15 Huppert, Deutsch. Arch.f. Hin. Med. 64. 129 (1899) ; Zeitschr. f. physiol. Chem. 

 23. 412 (1897) ; Xeubauer and Vogel's Harnanalyse, 10. Aufl., by H. Huppert, 

 Wiesbaden, 1898, p. 243. 



R. Kirk, from Huppert, Harnanalyse. 

 17 W. Falta and L. Langstein, Zeitschr. f. physiol. jflhem. 37. 513 (1903). 



I 



