434 JOSEPH H. PRATT 



and can under certain conditions be deposited as a homogeneous gelatinous 

 substance. 



The uric acid may occur in a form not demonstrable by Folin's method. 

 It was shown by S. Benedict to exist in ox blood almost entirely in the 

 combined form. Bornstein and Griesbach(fr), u.ing Benedict's method, 

 found in the cases of human blood they examined that about 50 per cent of 

 the uric acid was in a combined form. They examined only one case of gout 

 and in this case there had been no attack for several years. The free uric 

 acid was 1.84 mg., the combined uric acid 1.11 mg., making a total of 

 2.95 mg. per 100 c.c. of blood. Thannhauser and Czoniczer have shown that 

 adenin and the nucleosids do not give the uric acid reaction with phos- 

 photungstic acid until after boiling with mineral acid. These recent 

 findings open up new lines of investigation, and it is possible that in gouty 

 subjects the precursors of uric acid or combined uric acid are present in 

 larger amount or in different proportions than in health. 



Uric Acid in Joint Exudates in Gout 



Garrod(e) noted the presence of uric acid suspended in the fluid from 

 inflamed gouty joints. In its relation to the joints Friedrich Miiller has 

 called uric acid an arthrotropic substance. Bass and Herzberg attempted 

 to measure the degree of arthrotropia by comparing the amount of uric 

 acid in the joint fluids from gouty and non-gouty cases. The joint fluid 

 was obtained by puncture, usually post mortem, and the uric acid de- 

 termined in this as well as in the blood. Fluid from the knee joint was 

 chiefly used in these tests. In five non-gouty cases with exudate into 

 the joints the concentration of the uric acid in the joint fluid and in 

 the blood was practically the same. Two cases of gout were examined. 

 The values of the examinations was lessened by the fact that both patients 

 had uremia. 



TJric acid concentration. Uric acid concentration. 



Joint exudate Blood. 



Case I. Gout, ' Uremia 18.5 10.0 



" II. Chronic gout. Uremia 20.8 8.2 



The much greater concentration of uric acid in fluid from the knee 

 joints in gouty inflammations than in the blood suggests that determina- 

 tions of the uric acid in joint exudates would be of diagnostic value. I 

 have recently, however, examined the fluid from the knee in an undoubted 

 case of chronic tophaceous gout during an acute attack located in the foot 

 and knee. The blood contained 5 mg. of uric acid, but the clear fluid from 

 the knee contained only 3 mg. A few months later the patient died. 



