706 URINE. 



by several experimenters, 1 in great part destroyed and more or less com- 

 pletely changed into urea. As shown by WOHLER and FRERICHS for the 

 dog and by later investigators 2 also for cats, rabbits and other animals, 

 that allantoin is the most essential or indeed the chief decomposition 

 product is now considered as positively proven. In man, on the con- 

 trary, the conditions are different. According to WIECHOWSKI S probably 

 also a formation of allantoin from uric acid takes place in man, but it 

 is only of such an extent as to be without consideration, while in the dog 

 for example about 96 per cent of the purine base nitrogen may appear 

 as allantoin in the urine. According to the investigations of FRANK and 

 SCHITTENHELM 4 the uric acid in man is in part transformed into urea. 

 This different behavior of uric acid in the metabolism of man and 

 animals depends, as numerous investigations 5 have shown, upon the 

 occurrence of a urocolytic enzyme in the liver and also other organs of 

 animals, which transforms the uric acid into allantoin with the taking up 

 oxygen and splitting off of carbon dioxide. This enzyme, which has been 

 called uricolase and also uricase and whose occurrence in the organs of 

 different animals varies, is absent in the organs of man. The results 

 obtained in regard to the enzymotic transformation of uric acid by 

 experiments with organ extracts must be judged with the greatest care. 

 Thus according to the statements of WIECHOWSKI, BATTELLI and STERN 

 and ScmTTENHELM, 6 in dogs, the liver is the only organ which in a test- 

 tube shows a positive . uricoly sis; still in dogs, with excluded livers 

 (Eck fistula) such an abundant formation of allantoin from uric acid 

 occurs so that only 10-20 per cent of the uric acid escapes this trans- 

 formation. 7 



1 Wohler and Frerichs, Annal. d. Chem. u. Pharm., 65. See also Wiener, Ergeb- 

 nisse der Physiologie, 1, Abt. 1. 



2 Salkowski, Zeitschr. f. physiol. Chem., 35, and Ber. d. d. Chem. Gesellsch., 9; 

 Mendel and Brown, Amer. Jour, of Physiol., 3; Mendel and White, ibid., 12; Wie- 

 chowski, Arch. f. exp. Path. u. Pharm., 60, and Bioch. Zeitschr., 19 and 25, with Wiener, 

 Hofmeister's Beitrage, 9; Schittenhelm, Zeitschr. f. physiol. Chem., 62, with Seisser, 

 Zeitschr. f. exp. Path. v. Ther., 7; Abderhalden, London and Schittenhelm, Zeitschr. 

 f. physiol. Chem., 61. 



8 Bioch. Zeitschr., 25. 



4 Zeitschr. f. physiol. Chem., 63. 



5 Chassevant and Richet, Comp. rend. soc. biolog., 49; Ascoli, Pfliiger's Arch., 72; 

 Jacoby, Virchow's Arch., 157; Wiener, Arch. f. exp. Path. u. Pharm., 42, and Centralbl. 

 f. Physiol., 18; Schittenhelm, Zeitschr. f. physiol. Chem., 43, 45, and 63; Burian, 

 ibid., 43; Almagia, Hofmeister's Beitrage, 7; Pfeiffer, ibid., 7; Wiechowski and Wiener, 

 ibid., 9; Galeotti, Bioch. Zeitschr., 20; Battelli and Stern, ibid., 19; Scaffidi, ibid., 

 18; Miller and Jones, Zeitschr. f. physiol. Chem., 61; Wells, Journ. of biol. Chem., 7, 

 with Corper, ibid., 6. 



6 See Schittenhelm, Zeitschr. f. physiol. Chem., 63, 256. 



7 Abderhalden, London and Schittenhelm, 1. c. 



