188 Creatinine and Creatine in Blood 
first part of Table II arranged all the averages for plasma cre- 
atine (none of which is drawn from less than seven separate 
determinations) in ascending order of magnitude, placing beside 
each of them the average uriary creatine of the group to which 
it belongs. The figures are then seen to fall readily into three 
sets. In the first, consisting of four examples with a plasma 
creatine (corrected) of about 0.4, the urinary creatine is never 
greater than 5; in the second, two examples with a plasma creatine 
of 0.46, the urinary creatine lies between 8 and 15; while in the 
third, three examples with a plasma creatine of about 0.6, the 
urinary creatine ranges from 17 to 32. Unfortunately the evi- 
dential value of this apparent correspondence is not so great 
as it seems; for, in consequence of the occasional incompleteness 
of the analytical record, the respective averages for plasma and 
for urine are not invariably drawn from the same set of indi- 
viduals within the group which they are taken to represent. 
From this objection the figures which constitute the second part 
of Table IT are free. They are averages which have been com-- 
puted from those cases only in which both urine and plasma were 
successfully analyzed for creatine. The cases conforming to 
this requirement (46 in number) have been regrouped with refer- 
ence simply to the concentration in which creatine was being ex- 
creted at the time of the analysis. Thus in the first group (26 
cases) the urine was creatine-free; in the second (9 cases) it con- 
tained less than 10 mg. per 100 cc.; the third included all of the 
20 cases In which any creatine at all was present; while the fourth 
embraced those only (11) in which the concentration of creatine 
was higher than 10 mg. per 100 cc. The data yielded by these 
groups indicate with clearness the association of a regular in- 
crease in the average creatine content of the urine with an equally 
regular, though of course much more gradual rise in the average 
level of the plasma creatine. They therefore afford an un- 
equivocal confirmation of the conclusions to which the first 
part of the table had already pointed,—that the concentration of 
creatine in the urine bears a direct relation to that in the plasma, 
and that a slight increase in the Jatter (as little as 0.1 mg. per 100 
cc.) suffices to bring about a copious excretion. 
Had it been possible to put absolute confidence in the analytical 
data for plasma creatine, the last results would have demon- 
