156 PHYSIOLOGY OF PURIN METABOLISM 



disturbed uric acid synthesis. H. Wiener has noted in de- 

 hepatized birds that if the economy is experimentally flooded 

 with urea, lactic acid and especially, too, a number of di- 

 basic acids in whose structure there occurs a chain of three 

 carbon atoms, as malonic acid (COOH.CH 2 .COOH), tar- 

 tronic acid (COOH - CH(OH) - COOH) and mesoxalic acid 

 (COOH -CO -COOH) are capable of giving rise to an 

 increase in the uric acid elimination. The synthesis of uric 

 acid in such case may proceed somewhat as follows : 



LACTIC ACID TARTRONIC ACID DIALURIC ACID URIC ACID 



CH 8 COOH NH CO NH CO 



CH.OH >CH.OH > CO CH(OH) > CO C NH 



| + urea \ | + urea \ || \ m 



COOH COOH NH CO NH-C-NH/^' 



The recent recognition of a synthesis of uric acid from 

 dialuric acid and urea 20 may be regarded as the capstone of 

 the construction. 



An important recent investigation by Ernst Friedmann 

 and H. Man-del 21 would indicate that we are still far 

 from the truth. Contrary to Kowalewski and Salaskin, who 

 found an increase in the amount of uric acid in the blood 

 used in perfusion of the excised goose-liver after lactate of 

 ammonia was added, the above named authors were un- 

 able to in any way influence uric acid formation by introduc- 

 ing either lactate of sodium and urea, or malonate of sodium 

 and urea, On the contrary a remarkably large formation of 

 uric acid was a striking feature when perfusion was per- 

 formed with normal blood unchanged by any additions, 

 clearly not dependent upon washing out of previously 

 formed uric acid but indicative rather of an actual new 

 formation. This brings up the question whether perhaps 

 the synthesis of uric acid is not accomplished in a very dif- 

 ferent manner than indicated in the above schema. It is 



29 G. Izar (Ascoli's Lab., Catania), Zeitschr. f. physiol. Chem., 73, 317, 1911. 

 21 E. Friedmann and H. Mandel (First Med. Clinic, Berlin), Arch. f. exper. 

 Pathol. (Schmiedeberg Festschrift), p. 199, 1908. 



