536 ABNORMALITIES IN METABOLISM 



titles of blood, and other fluids, especially by Folin and Denis, Marshall, 

 and Van Slyke, has enabled us to obtain exact knowledge of many of 

 the chemical changes of nephritis and uremia.-^ It has been found 

 that the normal blood contains from 25 to 40 mg. of nitrogen in non- 

 coagulable form in each 100 c.c, there being usually about 5 mg. 

 increase after meals, and ordinarily about one-half of this nitrogen is 

 in the form of urea.^° In all conditions that impair renal function, 

 whether renal changes or circulatory deficiency, there is a rise in this 

 noncoagulable nitrogen, and when there is excessive tissue destruction 

 there may also be a sHght rise independent of renal injury. As a gen- 

 eral rule, but with some exceptions, the amount increases with in- 

 creased renal impairment, the highest figures being seen in uremia, in 

 which figures as high as 460 mg. have been obtained. In 130 nephritics, 

 Foster found the average to be 84 mg. of nitrogen. 



Analyses of the blood in 600 cases of nephritis by Get tier and St. 

 George^^ have given the following figures in mg. per 100 c.c. of blood: 



Normal Nephritis 



Nonprotein nitrogen 25 to 40 40 to 460 



Urea nitrogen 10 to 18 20 to 375 



Creatinin 0.1 to 0.8 2 to 42 



Uric acid 0.5 to 3.0 3 to 17 



Sugar 60 to 110 75 to 160 



Alkali reserve — per cent 53 to 80 40 to 75 



From their observations these authors conclude: All the waste 

 nitrogen products, nonprotein nitrogen, urea, creatinin and uric acid, 

 are present in increased amounts in cases of true nephritis, and gener- 

 ally, but not invariably, present in greater concentration in the blood 

 of those cases which are primarily considered as chronic interstitial 

 nephritis (retention nephritis"). The degree of retention (when taking 

 into account the functional efficiency of the cardiac muscle) is a direct 

 criterion of the severity of the lesion. The sugar content in the blood 

 is similarly increased in nephritis, and more marked in the patients 

 suffering with the chronic parenchymatous form of the disease. The 

 alkali reserve is a valuable index of the degree of acidosis present. 

 There is no definite lesion of nephritis referable to a certain clinical 

 picture. 



There is no constant relationship between the blood pressure and 

 the nitrogen figure, but functional tests usually show a correspondence 

 between the excretorj^ power of the Iddncy and the retention of meta- 

 boHtes in the blood. The symptoms of asthenic uremia are rarely 

 well defined when the concentration of urea in the blood is less than 



2^ Good reviews and bibliographies arc givtMi bv Tileston and Comfort, Arch. 

 Int. Med., 1914 (14), 620; Schwartz and McCiill, ibid., 1916 (17), 42; Woods. 

 ibid., 1915 (16), 577; Karsner, Jour. Lab. Clin. Med., 1916 (1), 910; Feigl, Biochem 

 Zeit., 1919 (94), 84. 



^" Sec Kast and Wardell, Arch. Int. Med., 1918 (22), 581. 



••".Jour. Amer. Med. Asso., 1918 (71), 2033. 



