43 
3. The peroxidase reagent, containing 0.032 gram of phenolphthalin, with 1 c. c. 
of X/10 sodium hydroxide and 0.1 c. c. of 3 per cent hydrogen peroxide. 
4. The alkaline phenolphthalin — hydrogen peroxide reagent, containing 0.032 
gram of phenolphthalin, 21 c. c. of N/10 sodium hydroxide, and 0.1 c. c, 
of 3 per cent hydrogen peroxide, made up with distilled water to 100 c. c. 
Tubes were prepared containing 2 c. c. of each of the above reagents 
and 1 c. c. of the solution to be tested or of distilled water. These 
were allowed to stand for one hour at ordinaiy temperature, at the 
end of which time 0.2 c. c. of X/10 sodium hydroxide was added to 
each of the tubes in which reagents 1 and 3 had been employed, and 
the colors noted. The results of these observations are given in 
Table I. 
Table I. 
Substance. 
Color produced with reagent — 
(1) 
(2) 
(3) 
(4) 
Water 
Colorless 
Colorless. 
Very light pink 
Very light pink. 
Malt (active) 
Colorless 
Colorless 
Deep purplish red 
Very light pink.® 
Malt (boiled) 
Colorless 
Colorless 
Light pink 
Very light pink.® 
Saliva (active) 
Colorless 
Colorless 
Light pink 
Very light pink.® 
Saliva (boiled) 
Colorless 
Colorless 
Colorless 
Very light pink.® 
Potato (active) 
Pink 
Yellowish 
Deep purplish red 
Light pinkish salmon. 
Potato (boiled) 
Colorless. 
Yellowish. . . 
Yellowish 
Light pinkish salmon. 
Blood (active) 
Colorless 
Pink 
Colorless, rapidly becom- 
Deep purplish red. 
ing pink and then red. 
Blood (boiled) 
Colorless 
Pink 
Colorless, rapidly becom- 
Deep purplish red. 
ing pink and then red. 
Horse-radish (active). 
Colorless 
Trace of 
Deep purplish red in- 
Faint pink. 
pink. 
stantly. 
Horse-radish (boiled). 
Colorless 
Colorless 
Purplish pink, much 
Trace of pink. 
lighter than unboiled 
specimen. 
M/lOOO copper sulfate. 
Colorless 
Colorless 
Deep purplish red prac- 
Deep purplish red. 
tically instantly. 
a Lighter than water control. 
In order to observe the effect of allowing these substances to stand 
in contact with the alkaline phenolphthalin reagent (2), certain of 
these tubes were allowed to stand, and examined at the end of three 
hours and twenty-four hours, with the folio vdng results: 
Substance. 
Color produced with reagent (2) after standing — 
3 hours. 
24 hours. 
Water 
Colorless 
Trace of pink. 
Deep purplish red. 
Light purplish red. 
Faint pink. 
Faint pink. 
Blood (active) 
Purplish pink 
Horse-radish (active) 
Trace of pink 
Horse-radish (boiled) 
Colorless 
M/lOOO copper sulfate 
Trace of pink 
