150 WALTER JOKES ^}: 



Finally, the nucleosides under proper enzymatic conditions decompose into 

 free purine and carbohydrate. 



HO- H 



H0\ ! H0\ 



I. 0-P O . C 5 H 8 3 . C 5 H 4 X 5 = 0=P . C 5 H 9 4 + C 5 H 5 N 5 * 

 HO/ HO/ 



adenine iiucleotide adenine 



HOH 

 H0\ H0\ 



II. O=P O ; C 5 H 8 O 3 . C 5 1I 4 X 5 - 0=P -OH-f-C 5 H 9 O 4 . C 5 H 4 N 6 

 HO/ j HO/ 



adenine nucleotide adenine nucleosidc 



III. C B H 9 4 .C 5 H 4 N 5 -f H 2 = C B H 10 O 5 + C.H.K, 



adenine nucleoside adenine 



Pitrine bases are, therefore, produced in the nuclein metabolism along 

 different lines, and their subsequent conversion into uric also occurs 

 along different lines. The intention of the following pages is a dis- 

 cussion of these various paths from nucleic acid to uric acid, and it would 

 be logical to proceed from nucleic acid, but it is more convenient to be- 

 gin at the end, and end at the beginning. 



The Formation of Uric Acid from Nucleic Acid. Uric acid was for- 

 merly supposed to be an intermediate product in protein metabolism, but 

 its specific origin was clearly indicated when the purine groups of nucleic 

 acid- were discovered; and endeavors were naturally 'made to place this 

 indication on an experimental basis, llorbaezewski (b)(c} (1880, 1801) 

 was the first to do this. His results are fundamental and quickly told. 

 Calf's spleen was ground to a pulp with water, and kept at the body tem- 

 .perature until putrefaction was well advanced. The putrid product was 

 then sterilized by the addition of lead acetate, arterial blood was added, 

 and the material was allowed to digest at 40 as a slow stream of air was 

 passed. In the end, uric acid could be found, while similar experiments in 

 which no air was passed produced xanthine and hypoxanthine instead of 

 uric acid. 



Horbaczewski did not clearly understand what he was doing and took 

 a great, deal of useless trouble. The preliminary putrefaction and the 

 use of arterial blood were superfluous procedures while the sterilization 

 witli lead acetate might have vitiated his results. Nevertheless, he started 

 with nucleic acid of spleen pulp and ended with uric acid. 



Horbaczewski also found that in man the ingestion of nucleic acid pro- 



