100 
IOWA ACADEMY OP SCIENCE 
the nature of these ferments and the conditions which may modify their action 
in the human body. In order to simplify the problem the exogenous uric acid 
was excluded by limiting the subjects to a purin-free diet. This consisted of the 
wheat foods, milk, eggs, cheese, butter, with no potatoes or very little. The kinds 
and amounts were practically the same each day of the experiment. As has 
been found by a number of investigators the endogenous uric acid of the same 
individual, although there may be variations from day to day, has a remarkably 
constant average amount. Hence on such a diet as the above the effect of chang- 
ing the other conditions can be readily seen. The experiments here described 
were made in the attempt to learn of the modification of the action of the 
uricolytic and uric acid forming ferments from the administration of drugs. 
As is well known, salicylic acid (ortho-hydroxy-benzoic acid), 
V 
markedly increases the output of uric acid in the urine, where it makes up about 
nine-tenths of the total pur ins. Not only the free acid, but also its salts and 
some other derivatives like aspirin (the acetic acid ester of salicylic acid) do 
this. Among the drugs used were the isomers of salicylic acid^ meta-hydroxy- 
ihenzoic acid, 
A CO2H 
I I OH 
V 
and para-hydroxy-benzoic acid, 
A CO2H 
\j OH 
The endogenous uric acid was determined for a drug-free period, usually of 
several days, then the amount eliminated during the administration of the drug 
and also in an after period when no drug was taken. The uric acid was de- 
termined by Folin’s method, as was the creatinin; nitrogen by Kjeldahl’s method 
and phosphoric acid by titration with uranium acetate. The results are shown 
below: 
