BODY TISSUES AND FLUIDS 437 



favorable. Nephritis in children does not so quickly result in urea 

 retention as in the adult. On this account it is an especially helpful 

 prognostic test in the nephritis occurring in early life. 



Uric Acid. No accurate figures on the uric acid content of normal 

 human blood were available until the introduction of the colorimetric 

 method of Folin and Denis (e) in 1913. In a series of unselected cases Fo- 

 lin and Denis (&) found between 1 and 3 mg. to 100 c.c. of blood, the aver- 

 age being close to 2 mg. Although the accuracy of the method of estimating 

 uric acid has been considerably improved, still the figures which are now 

 regarded as normal for the blood uric acid differ very little from those 

 originally reported by Folin and Denis. Healthy adults most often yield 

 values between 2 and 3 mg. per 100 c.c. of blood, but figures as low as 

 1 mg. and as high as 3.5 mg. may be encountered in strictly normal indi- 

 viduals, the difference probably depending in part upon dietary factors. 

 High blood uric acids must obviously depend upon either an increased for- 

 mation or a decreased elimination. 



In leucemia the first factor accounts for the increase, but high uric 

 acids in most other conditions find a probable explanation on the latter 

 basis. Among these may be mentioned nephritis, acute and chronic (but 

 not parenchymatous), arterial hypertension, lead poisoning, bichlorid 

 poisoning, malignancy, acute infections, especially pneumonia, gout and 

 apparently some cases of non-gouty arthritis. Miscellaneous cases illus- 

 trating the uric acid findings in many of these conditions are given in the 

 urea table above. Sedgwick and Kingsbury have made the interesting ob- 

 servation that the blood uric acid is high during the first three or four days 

 of life, in harmony with the high uric acid excretion during that period. 



That the uric acid content of the blood was increased in gout was 

 recognized more than seventy years ago by Sir A. B. Garrod. He put 

 the subject of the uric acid content of the blood on a definite' basis when 

 he identified this substance in the blood of patients suffering from gout, 

 and showed that whereas uric acid was normally present in blood only in 

 traces, it was definitely increased not only in gout, but also in certain 

 cases of nephritis. He further showed that there is no increase in the 

 blood uric acid in rheumatism, such as is found in gout, and used this as 

 a point of differential diagnosis. No noteworthy advance in this subject 

 was made until the advent of the colorimetric method of Folin and Denis 

 previously referred to. 



In their original paper Folin and Denis (6) found practically no eleva- 

 tion of the uric acid in a series of eleven nephritic bloods with only mod- 

 erate nitrogen retention, but later they reported data on cases of advanced 

 nephritis in some of which very high values were obtained, up to 10 

 mg. These latter observations were confirmed by Myers and Fine (#), who 

 noted very high figures for uric acid in several cases of terminal interstitial 

 nephritis. In one case the uric acid reached the enormous figure of 27 mg. 



