166 PHYSIOLOGICAL CHEMISTRY 



The question has been raised, can the body build up its own 

 purines (and from these its nucleoproteins) from non-purine 

 substances? This question is as yet unanswered. In birds and 

 reptiles the synthesis of uric acid is a well known fact. In 

 invertebrates also this synthesis takes place. It would be curious 

 if only mammals lacked this power. We know in fact that in 

 very young mammals living on milk, which contains only traces 

 of purine, large amounts of nuclear material are built up, 

 apparently from non-purine sources. But the question is still 

 unsettled, and awaits further evidence. 



The variations in the amount of uric acid in disease are in- 

 fluenced by the amount of destruction of nuclear material in the 

 body. During recovery from pneumonia, when the transudates 

 containing large numbers of leucocytes are being reabsorbed, in 

 leucemia where the number of leucocytes in the blood is great- 

 ly increased, after severe burns which have caused the disin- 

 tegration of much tissue and in pregnancy when there is in- 

 creased nuclear metabolism, an increase in uric acid is ob- 

 served. In gout and arthritis uric acid is deposited in the joints 

 causing much pain and inconvenience. It is a debated question, 

 however, as to whether this is the cause or the effect of the dis- 

 ease. 



Other purines occur in the urine in small quantities. Also 

 caffein, theobromine and other members of the group which 

 occur in coffee, cocoa, etc., may be present. The quantitative esti- 

 mation of uric acid is described in the laboratory directions. 



Hippuric Acid. 







C C NH CH 2 COOH 



//\ 

 HC CH 



I II 



HC CH 



\/ 

 C 

 H 



