31 ' 
In order to test the conduct of these blood solutions towards an 
alkaline solution of phenolphthalin containing no hydrogen peroxide, 
tubes were prepared containing 2 c. c. of the alkaline phenolphthalin 
solution and 1 c. c. of blood solutions Xos. (1), (2), (3), and (4), and 
also a control containing 2 c. c. of alkaline phenolphthalin and 1 c. c. 
of distilled water. These were allowed to stand for eighteen hours 
at ordinary temperature; at the end of this time the tubes had 
developed colors as follows: 
Test. 
Quantity of blood, 
gram. 
Color. 
Control 
None. 
Trace of pink. 
Number (1) 
0. 000038 
Deep purplish red. 
Number (2) 
.0000038 
Deep purplish pink. 
Number (3) 
. 00000038 
Light pink. 
Number (4) 
. 000000038 
Trace of pink. 
Xo difference in color could be made out between the control and 
No. (4). Hence so far as the oxidation of alkaline phenolphthalin 
can be accomplished by blood alone without li 5 xlrogen peroxide, 
0.00000038 gram of blood at a dilution of 3 c. c., or approximately 
1 part of blood in 8,000,000, is about the limit of the reaction. 
THE QUANTITY OF PHENOLPHTHALIN OXIDIZED UNDER THE 
INFLUENCE OF BLOOD IS PROPORTIONAL TO THE QUANTITY 
OF BLOOD PRESENT. 
It was shown by Kastle and Amoss (80) that the oxidizing power 
of the blood of different individuals is proportional to the hemo- 
globin content. It seemed of interest, therefore, to determine in 
this connection the oxidizing power of the blood of the same indi- 
vidual at different concentrations. Accordingly 3.5 milligrams of 
blood from one individual was dissolved in 100 c. c. of water. Five 
c. c. of this solution were made up to 10 c. c. with distilled water, 
10 c. c. were made up to 50 c. c., 10 c. c. were made up to 100 c. c. 
These solutions, therefore, had the relative concentrations of 1.0, 
0.5, 0.2, and 0.1, respectively. The oxygen-carrying power of these 
solutions was then tested toward the alkaline phenolphthalin-hydro- 
gen peroxide reagent, using 2 c. c. of the reagent and 1 c. c. of each of 
the blood solutions. The four tubes containing these mixtures were 
allowed to stand one hour at ordinary temperature, at the end of 
which time they were compared as to color in the Duboscq colorim- 
eter with the following results: 
Concentration 1.0 0.5 0.2 0.1 
Scale reading 1.0 2.0 4.6 9.6 
The oxidizing power of these solutions was also tested toward 
alkaline phenolphthalin, using 2 c. c. of the reagent with 1 c. c. of 
