138 THE ADRENALS AND THE GENERAL OXIDATION PROCESSES. 



uric acid. These results were sustained by Kuhnau, who ob- 

 served that pure nuclein administered in large doses was elim- 

 inated in the form of uric acid, and further confirmed by 

 Weintraub, Umber, and Mayer after a series of counter-experi- 

 ments. 



Dunin and Nowaczek 6 studied the question from another 

 direction: i.e., in five cases of pneumonia, in which disease, as 

 we have seen, leucocytosis is very marked. They found that 

 the quantity of uric acid eliminated rises greatly the day before 

 the crisis: i.e., when absorption of the exudation and destruc- 

 tion of the leucocytes begin. Immediately after the crisis the 

 uric-acid ratio rose to three times that of the precritical period, 

 and continued high several days. It seems plain, therefore, 

 that uric acid originates from nucleins, which in turn are de- 

 composition products of the cells of the organism and particu- 

 larly of leucocytes. 



The nuclein derivatives, hypoxanthin, guanin, xanthin, 

 just referred to and another, adenin, of the same class have 

 since been termed "alloxuric bases" by Kossel and Kruger, but 

 E. Fischer, after exhaustive investigations, traced them all to 

 a carbon-hydrogen nucleus, the purin nucleus, from which 

 many important derivatives uric acid, caffeine, theobromine, 

 etc., besides the nuclein bases mentioned above can be ob- 

 tained. This feature obviously demonstrated a close chemical 

 relationship between these bodies and various substances 

 cocoa, coffee, tea, meats, sweet-bread, liver, and others rich in 

 nucleins, and normally led to the conclusion that articles of 

 food which had long been associated pathogenically with the 

 production of uric acid, could also act as sources of nuclein 

 bases. This was confirmed by experiments in healthy subjects, 

 from whose urine the latter were obtained daily in varying 

 proportions. 



It then became a question as to which of the two sources 

 of nuclein prevailed: i.e., whether they were derived from body- 

 cells, leucocytes, etc., as thought by Horbaczewski, or from 

 articles of food, as thought by Fischer. Experimental data in 



Dunin and Nowaczek: Zeitschrift fur klin. Med., Bd. xxxii, 1897. 



