824 



PHYSIOLOGY 



The foods which are especially effective in causing increase in the 

 exogenous uric acid are those rich in nuclein, such as sweetbreads or liver, 

 and those rich in hypoxanthine or its precursors, such as meat or meat 

 extract. 



When these foods are taken, or when nucleic acid itself is administered, a con- 

 dition of leucocytosis is generally produced, the number of leucocytes in the blood 

 being increased as much as three times. It has been suggested that the uric acid is 

 actually formed by a disintegration of the newly formed leucocytes and not by a direct 



20 



11 12 1 



10 Jl 17 



FIG. 366. Curves showing the hourly excretion of uric acid and urea after a single 

 meal. (HOPKINS.) The continuous line = uric acid output; the dotted 

 line = urea output. 



conversion of the purines of the food. It is quite possible, as suggested by Schittenhelm, 

 that the leucocytes play a part in the transference of the nucleins from the intestine 

 to the circulation. But the absence of any absolute proportionality between the degree 

 of leucocytosis and the amount of uric acid excreted points to the probability of a direct 

 conversion of the purines of the food into uric acid. 



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 production of uric acid be largely increased 

 by the administration in large quantities of foodstuffs 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 re- 

 garded, 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 sub- 

 stance by the kidneys. This view is difficult to reconcile with the fact that, if uric 

 acid be injected subcutaneously into gouty subjects, it is stated to be excreted in the 

 urine exactly in the same way and as rapidly as in normal persons. It has been 

 suggested that gout consists essentially in a disturbance in the various fermentative 

 mechanisms which are responsible for the changes undergone by the purines, so that 



