47 
In order to form a better idea of the extent of the oxidation in 
certain of these solutions, the following, Nos. 1, 9, 10, 11, and 23, 
were compared in the Duboscq colorimeter with solution No. 2, con- 
taining blood, with the following results : 
Solution. 
Substance. 
1 
. Readings on colorimeter scale. 
Substance. 
' Blood (No. 2). 
Number 1 
Water 
! 10 
0.1 
Number 9 
Potassium ferrocyanide 
1 
10 
.4 
Number 10 
Potassium ferricyanide 
' 10 
2.0 
Number 11 
Sodium nitroprusside 
. ' 10 
2.0 
^umber 23 
Potassium cblorplatinate 
10 
1 
.7 
Or, in terms of the color of the solution of blood arbitrarily made 
equal to 100, the colors produced with the other substances have the 
following values : 
1 
Substance. 
Color. 
Blood 
100 
Water 
1 
Potassium ferrocyanide 
4 
Potassium cblorplatinate 
7 
Potassium ferricyanide 
20 
Sodium nitroprusside 
20 
It is evident from these results that at the concentration of 100 
milligrams per liter none of the 23 substances investigated have an 
oxygen-carrying power towards alkaline phenolphthalin at all com- 
parable vuth that of blood, only 3 out of the 23 showing decided 
oxidizing power, viz, silver nitrate. No. 19, potassium ferricyanide 
No. 10, and sodium nitroprusside. No. 11, and even with these only 
one-fifth as much phenolphthalein was produced as with blood. 
