BODY TISSUES AND FLUIDS 



433 



there may be at first only a slight rise in the uric acid or urea, although 

 in the terminal stages of the disease there is generally a very marked ele- 

 vation in all the forms of non-protein nitrogen. The normal range of the 

 various non-protein nitrogenous components is given in the table below. 

 Data are also included indicating the deviations which may occur in gout 

 interstitial and parenchymatous nephritis and eclampsia. 



As will be noted in the table, the normal range for the non-protein 

 nitrogen is given as 25-30 mg. per 100 c.c. of blood. In discussing the 

 question of the normal values for the non-protein nitrogen there are two 

 very important factors which should always be considered, viz., the protein 

 precipitant employed and the proximity to the last meal, the results re- 

 ported with the original method of Folin and Denis (/) are probably a little 

 too low, owing to the use of methyl alcohol as the protein precipitant. 

 Folin and Denis originally obtained figures of 22-26 mg., while Tileston 

 and Comfort found 23-25 mg. with a series of five normal adults in a fast- 

 ing state, and 26-32 mg. two and a half hours after a heavy protein 

 meal. More satisfactory results are obtained after the trichloracetic 

 acid precipitation of Greenwald (d) or use of the tungstic acid reagent re- 

 cently employed by Folin and Wu. After these methods of precipitation 

 figures close to 30 mg. are generally obtained on a normal individual in 

 the fasting state. 



NONPROTEIN NITROGENOUS CONSTITUENTS, MG. TO 100 c.c. OF BLOOD 



The figures for the normal creatin are taken from observations of Denis, those 

 for amino-acid nitrogen from Bock, except in the case of eclampsia, where the observa- 

 tions of Losee and Van Slyke are recorded; other data in eclampsia are from recent 

 observations of Killian. With these exceptions the data are from the writer's observa- 

 tions. 



The figures for ammonia are very small, but these figures may be taken as the 

 maximal rather than the minimum values. The very recent observations of Nash and 

 Benedict on the ammonia content of the blood (made on dogs and cats) give figures 

 between 0.03 and 0.2 mg. to 100 c.c. 



The origin and role which the various non-protein nitrogenous constit- 

 uents play in metabolism, as well as the ease of kidney secretion, obviously 

 greatly influence the content of these substances in the blood, both normally 

 and pathologically. Folin's classic papers on the composition of urine 

 (for discussion, see Chapter IV) published in 1005, did much to give 



