19 
Table No. 1. 
[Series No. 1 (for several intervals).] 
Date. 
Name of 
person. 
Condition. 
Per 
cent of 
hemo- 
glo- 
bin. 
Colorimeter readings at 
the end of intervals 
indicated compared 
with standard phen ol- 
phthalein solution, set 
at 5 divisions on the 
^colorimeter scale. 
5 min- 
utes. 
15 
min- 
utes. 
1 
hour. 
24 
hours 
Amoss . . 
Collier.. 
Hynson. 
Normal 
Pernicious anemia . 
do 
96 
20-21 
27 
8. 75 
16.5 
16.5 
3.3 
8.8 
7.2 
2.6 
8. 45 
6.1 
3.4 
19.5 
11.6 
Quantity of phenolphthal- 
ein formed, in milli 
grams, during the sev- 
eral intervals. 
omin- 
0. 1S2 
.096 
.096 
15 
min- 
utes. 
1 
hour. 
0. 481 
.181 
. 221 
24 
hours. 
0. 612 0. 468 
. 188 . 0816 
. 261 . 137 
Date. 
Name of 
person. 
Quantity of phenolphthalin oxidized, 
in milligrams, during the several 
intervals. 
Percentage of oxidation during the 
several intervals. 
5 min- 
utes. 
15 min- 
utes. 
1 hour. 
24 hours. 
5 min- 
utes. 
15 min- 
utes. 
1 hour. 
24 hours. 
Apr. 22 
Amoss 
0.183 
0.484 
0. 616 
0. 471 
11.4 
30.2 
38.5 
29.4 
22 
Collier 
.097 
.182 
.189 
.082 
6 
11.3 
11.8 
5.1 
22 
Hynson... 
.097 
.222 
.263 
.138 
6 
14 
16.4 
8.6 
FADING OF THE PHENOLPHTHALEIX COLOR. 
Reference has already been made to the fact that the color of 
the phenolphthalein solution resulting from the oxidation of plienol- 
phthalin by hydrogen peroxide under the influence of minute quanti- 
ties of blood gradually fades somewhat, so that apparently the quan- 
tity of phenolphthalin oxidized at the end of twenty-four hours is 
less than the amount oxidized during one hour. 
That such is the case is evident from the results given in Table Xo. 1. 
An examination of these results shows an increase in the amount of 
oxidation up to the end of one hour, after which a gradual fading of 
the color of the solution occurs until, at the end of twenty -four hours, 
the amount of phenolphthalin oxidized is apparently from one-quarter 
to one-half less than the amount oxidized at the end of one hour. 
Without it is that the blood contains a substance capable of reducing 
phenolphthalein — and this, of course, is conceivable — it is difficult to 
see why less phenolphthalin should be oxidized at the end of twenty- 
four hours than at the end of one hour. As a matter of fact the 
fading out of the phenolphthalein color seems to depend upon several 
causes. 
In the first place, it seems to depend upon the character of the 
blood, being greater and more rapid in the case of diseased bloods, 
poor in hemoglobin. The result is that the most striking differences 
between normal and diseased bloods are revealed after the longer 
