704 UKINE. 



although, as SALASKIN and ZALESKI and LANG have shown, after the 

 extirpation of the liver, and increase in the formation of lactic acid pri- 

 marily occurs, and this causes an increase in the elimination of ammonia 

 (neutralization ammonia). The direct proof for the uric-acid formation 

 from ammonia and lactic acid in the liver of birds has been given by 

 KOWALEWSKY and SALASKIN 1 by means of blood-transfusion experiments 

 on geese with extirpated livers. -They observed a relatively abundant 

 formation of uric acid after the addition of ammonium lactate and a 

 still greater formation after arginine. They not only consider ammonium 

 lactate but also amino-acids as substances from which the uric acid can 

 be produced in the liver by synthesis. That these, for example, leucine, 

 glycocoll, and aspartic acid, increase the elimination of uric acid in 

 birds was first shown by v. KNiERiEM. 2 



The possibility of a formation of uric acid from lactic acid has been 

 shown in another manner by WIENER, S namely, by feeding birds with 

 urea and lactic acid and different non-nitrogenous substances, oxy-, 

 keto-, and dibasic acids of the aliphatic series. The dibasic acids, with a 

 chain of 3 carbon atoms or their ureides, showed themselves most active 

 as uric-acid formers, and WIENER is therefore of the opinion that the 

 active substances must first be converted into dibasic acids. By the 

 attachment of a urea residue the corresponding ureide is produced, 

 according to WIENER, and from this the uric acid is derived by the attach- 

 ment of a second urea residue. 



Among the substances tested, only tartronic acid and its ureide, dialuric acid, 

 have shown themselves active in the experiments with the isolated organs, and 

 WIENER therefore also considers that the other acids must be first converted into 

 tartronic acid by oxidation or reduction. From lactic acid, CH 3 .CH(OH).COOH, 

 we first obtain tartronic acid, COOH.CH(OH).COOH, which by the attachment 



/NH C0\ 

 of a urea residue forms dialuric acid, C0\ /CHOH, and from this, by 



\NH CO/ 

 the attachment of a second urea residue, uric acid is formed. 



Recently IzAR 4 has shown on perfusing blood containing urea and 

 dialuric acid through the liver of a dog and at the same time saturating 

 the blood with carbon dioxide, that an abundant formation of uric acid 

 occurred, and that a combined action between an enzyme occurring 



1 v. Schroder, Zeitschr. f. physiol. Chem., 2; Meyer and Jaffe, Ber. d. f. Chem. 

 Gesellsch., 10; Minkowski, Arch. f. exp. Path. u. Pharm., 21 and 31; Salaskin and 

 Zaleski, Zeitschr. f. physiol. Chem., 29; Lang, ibid., 32; Kowalewsky and Salaskin, 

 ibid., 33. 



2 Zeitschr. f . Biologic, 13. 



3 Hofmeister's Beitrage, 2. See also Arch. f. exp. Path. u. Pharrn., 42, and Ergeb- 

 nisse d. Physiol., 1, Abt. 1, 1902. 



4 Zeitschr. f. physiol. Chem., 73, see also ibid., 65. 



