A. Hunter and W. R. Campbell 179 
A comparison of this corrected average with the averages for 
the two corresponding groups of plasmas (1.09 and 1.03) shows 
that the difference in the creatinine content of whole blood and 
plasma is in reality practically negligible. It is, of course, not 
possible to say that there may not be in individual specimens a 
slight excess of creatinine in corpuscles or in plasma; but the 
conclusion to which the twenty-seven results considered indubitably 
appear to point is that in general the creatinine of normal human 
blood is ‘distributed among its different elements at a practically 
uniform concentration. Our previously expressed opinion upon 
the point is therefore abandoned, and the contention of Wilson 
and Plass sustained. Ke 
Lacking quantitative data upon the average error of the 
Myers’ technique, we are unable to apply any appropriate 
correction to results obtained upon blood which had been laked. 
Those figures, therefore, which are in parentheses in the table, can- 
not be utilized in the present argument. It will be noticed 
that the disproportion between them and the corresponding plasma 
results is in general greater than in the case of unlaked blood. 
Thus, the average for all 60 bloods, including as it does 33 which 
were laked, is not 50 but 75 per cent higher than the plasma 
average; and in individual cases, especially, it would seem, among 
puerperal women, laked blood appears to have twice or even 
thrice as much creatinine as its plasma. All this is in accord with 
our previous observations, and those of Wilson and Plass, upon 
the excessive tendency of the Myers’ procedure to exaggerate the 
whole blood creatinine. It may be remarked, though, that this 
tendency is much less obvious in the strictly normal cases of 
Group I than in either. of the other groups. 
The conclusion that the creatinine content of blood is in 
reality the same as that of its plasma has an obvious bearing 
upon the question of the normal limits within which the whole 
blood creatinine may range. According to Folin and Denis?’ 
these are 1.0 to 1.4 mg. per 100 cc.; according to Myers and 
Fine,”® 1.0 to 2.0. With such estimates as these our own uncor- 
rected results with whole blood are in substantial agreement. 
27 Folin, O., and Denis, W., J. Biol. Chem., 1914, xvii, 487. 
28 Myers and Fine, Post-Graduate, 1915, xxx, 39. 
