702 URINE. 



we consider the formation of uric acid from the purine bases of the nuclein 

 substances as a positively proven fact. 



According to the original view of HORBACZEWSKI the nucleins do 

 not directly (by their purine bases) cause an increased elimination of uric 

 acid, but indirectly by causing a leucocytosis with a consequent destruc- 

 tion of leucocytes. This view has been justly discarded on account, 

 of the above-mentioned conditions; still on the other hand it cannot 

 be denied that the formation of uric acid is als'o in certain regards related 

 to the formation or the destruction of leucocytes and to the metabolism 

 in the cells as a whole. 1 



The uric acid, in so far as it is produced from nuclein bases, is in part 

 derived from the nucleins of the destroyed cells of the body and in part 

 from the nucleins or free purine bases introduced with the food. It 

 is therefore possible to admit, with BURIAN and ScnuR, 2 of a double origin 

 for the uric acid as well as the urinary purines (all purine bodies of the 

 urine, including the uric acid), namely, an endogenous and an exogenous 

 origin. BURIAN and SCHUR attempted to determine the quantity of 

 endogenous urinary purines by feeding with sufficient food, but as free 

 as possible from purine bodies, and they found that this quantity was 

 constant for every individual, while it was variable for different persons. 

 The observations of many other investigators have led to similar con- 

 clusions, and we are now unanimous in our opinion that the uric acid 

 originating from the nucleins is partly endogenous and partly exogenous, 

 and that the amount of endogenous uric acid is only very slightly dependent 

 upon the protein content of the food. 



The formation of uric acid from the nucleins or the purine bases seems 

 at least in great part to be of an enzymotic kind. After it was shown that 

 certain organs, such as the liver and spleen, had the power of converting 

 oxypurines into uric acid in the presence of oxygen (HORBACZEWSKI, 

 SPITZER and WIENER 3 ), recently SCHITTENHELM, BURIAN, JONES and 

 co-workers 4 , by more careful investigations have shown that enzymes 



der Physiol., 1, Abt. 1, 1902. See also Schittenhelm, Zeitschr. f. physiol. Chem., 62, 

 with Frank, ibid., 63, with Seisser, Zeitschr. f. exp. Path. u. Ther., 7; Abderhalden, 

 London and Schittenhelm, Zeitschr. f. physiol. Chem., 61; Mendel and Lyman., Journ. 

 of biol. Chem., 8. 



1 See Plimmer, Dick and Lieb, Journ. of Physiol., 39; Mares Pfliiger's Arch., 134, 

 and Smetanka, ibid., 138. 



2 Pfliiger's Arch., 80, 87, and 94. 

 1 See footnote, 6, page 701. 



4 Schittenhelm, Zeitschr. f. physiol. Chem., 42, 43, 45, 46, 57, 63, 66, with Schmid, 

 ibid., 50, and Zeitschr. f. exp. Path. u. Therap., 4; Burian, Zeitschr. f. physiol. 

 Chem., 43; Jones and Partridge, ibid., 42; Jones with Winternitz, ibid., 44 and 60; 

 Jones, ibid., 45, 65, with Austrian, ibid., 48, with Miller, ibid., 61; Jones, Journ. of 

 biol. Chem., 9; Wells, ibid., 7; Mendel and Mitchell, Amer. Journ. of Physiol., 20. 



