FORMATION OF UKIC ACID. 705 



in the blood and an alcohol-soluble co-enzyme occurring in the liver 

 and spleen took place. He has besides this also given further proof of 

 the formation of uric acid in the bird-liver from urea and ammonium 

 carbonate. 



We cannot give any positive answer as to the question whether uric 

 acid is formed by synthesis in man and other mammalia. WIENER 

 has reported experiments which seem to indicate a synthetic uric-acid 

 formation in the isolated mammalian liver, and he has also obtained 

 an increase in the uric-acid elimination, although only a slight one, after 

 feeding lactic acid and dialuric acid to man. In opposition to these 

 experiments PFEIFFER 1 could find no increase in the elimination of 

 uric acid after feeding malonamide and tartronamide to monkeys as 

 well as tartronic acid and pseudouric acid to monkeys or human beings, 

 and he finds that a synthesis of uric acid in mammalia and man is very 

 doubtful. According to BuRiAN 2 we have for the present no proof 

 of a synthetical formation of uric acid in the mammalian liver; in 

 view of the above-mentioned experiments of IZAR, we cannot deny the 

 possibility of a synthetical formation of uric acid also in mammalia and 

 man even if we do not know to what extent this occurs. 



The liver seems to be the organ in birds where the synthetical forma- 

 tion of uric acid occurs, and the fact that it was possible for MINKOWSKI 3 

 to arrest the uric-acid formation by the extirpation of the liver, apparently 

 shows that the liver is the only organ taking part in this synthesis. If a 

 synthesis of uric acid also occurs in man and other mammalia, we must 

 consider the liver as at least one of the organs taking part in the work, 

 as shown by WIENER'S and IZAR'S investigations. The liver is considered 

 as the most important organ in the oxidative formation of uric acid from 

 nucleins and purine bases. That this organ, at least in the dog, is not 

 the only or at least not the most important follows from the investiga- 

 tions of ABDERHALDEN, LONDON and SCHITTENHELM 4 on dogs with Eck 

 fistula. They found that, on excluding the liver in this manner, that the 

 transformation of the nucleic acid fed, the deamidation of the purine 

 bases and the oxidation of these into uric acid and allantoin was 

 undisturbed. In the dog also other organs must be considered in 

 this connection. It is not known how other animals behave in this 

 regard. 



'Uric acid when introduced into the mammalian organism is, as first 

 shown by WOHLER and FRERICHS, in the dog, and later substantiated 



1 Hofmeister's Beitrage, 10. 



2 Zeitschr. f. physiol. Chem., 43. 



3 I.e. 



4 Zeitschr. f. physiol. Chem., 61. 



