882 PHYSIOLOGY 



probability of a direct conversion of the purines of the food into 

 uric acid. 



In man only very small traces of allantoin are to be found in the 

 urine, so that we must assume that any uric acid which is destroyed 

 by the process of uricolysis is broken down into urea, and probably 

 appears as such in the urine. 



URIC ACID IN GOUT 



Gout is a condition in which deposits of urate of soda occur in the 

 cartilages of the joints, the great toe joint being the seat of predilection 

 for this disorder. The deposit is generally associated with an acute 

 inflammation of the joint. In normal individuals the amount of uric 

 acid in the blood is too small to be detected. Uric acid is readily 

 excreted by the healthy kidneys. If the output of uric acid be largely 

 increased by the administration in large quantities of food-stuffs rich 

 in purines, it becomes possible to demonstrate the actual presence 

 of uric acid in the blood. In gout there is constantly an increased 

 amount of uric acid in the blood, probably in the form of sodium 

 urate, even when the patient is on a purine-free diet, so that gout may 

 be regarded, from one point of view at any rate, as a uricaemia of 

 endogenous origin. On the other hand, the output of uric acid in the 

 urine is not increased, and may in fact be somewhat smaller than 

 normal. It might be thought that the presence of uric acid in the 

 blood must therefore be due to diminished power of excretion of this 

 substance by the kidneys. This view is negatived by the fact that if 

 uric acid be injected subcutaneously into gouty subjects it is excreted 

 in the urine exactly in the same way and as rapidly as in normal 

 persons. It has therefore been suggested that gout consists essentially 

 in a disturbance in the various fermentative mechanisms which are 

 responsible for the changes undergone by the purines as well as by the 

 uric acid itself, so that there is an increased amount not only of uric 

 acid itself but of the various intermediate products in its formation 

 from the purine bases of the food and of the tissues. The deposit of 

 the uric acid in the joint cartilages characteristic of acute gout seems 

 to be simply a crystallisation of urate of soda from a supersaturated 

 solution of this substance in the blood. The whole question of the 

 pathology of gout and of the disordered metabolism which may 

 precede or intervene between actual acute attacks of the disease is 

 in need of further investigation. Especially is it important to deter- 

 mine the influence on this condition not only of the nucleins and 

 proteins of the food, but of the other constituents, such as carbo- 

 hydrates and fats. Speaking broadly, gout is a disease of the 

 well-to-do, of the person who, while pursuing a sedentary or no occupa- 

 tion, is not limited in his food-supply. It is almost unknown in the 



