indigo-blue coloration with guaiacum, whereas the boiled control gave 
no coloration with this reagent. 
EFFECT OF HEAT OX THE OXIDASES OF LEPIOTA AMERICANA, 
In the preceding part of this paper repeated reference has been 
made to the fact that the boiled controls of various extracts and prep- 
arations of the fungus gave no reaction with guaiacum. 
It seemed of interest, therefore, to determine more carefully the 
effect of heat on the activity of the oxidases here under investigation. 
An aqueous solution of the alcoholic precipitate, described under the 
preceding head, was employed in these experiments. In order to deter- 
mine the effect of heat on the activity of the oxidases, small bore test 
tubes containing 1 c.c. of the solution were immersed in water baths, 
the temperature of which was carefully regulated. After remaining 
in the bath for the desired interval, the tubes were removed and 
quickly brought to ordinary temperature and tested wdth guaiacum. 
The results of these observations are given in the following table: * - 
Temperature. 
• 
Time of ex- 
posure in 
minutes. 
Color with guaiacum. 
80° C 
5 
Light blue. 
80° C 
10 
Lighter blue. 
80° C 
30 
Trace of blue. 
80° C 
60 
None. 
85° C 
2 
Faint blue. 
85° C 
5 
Trace of blue. 
85° C 
10 
None. 
86° C 
4 
Do. 
90° C 
1 
Do. • 
90° C 
1 
Trace of blue. 
90° C 
1 
Do. 
90° C 
5 
None. 
90° C 
10 
Do. 
At temperatures below 80° C. , an hour’s exposure was found to be 
insufficient to destroy the oxidizing power of this solution. It will be 
seen from our results, therefore, that the destruction temperature for 
the oxidases of Lepiota americana lies between 80 c and 90 C C., and 
that an exposure to a temperature of 80° C., for a comparatively short 
time, is insufficient to render these oxidizing substances inert. 
The relatively high destruction temperature of these oxidases is in 
keeping with their remarkable stability at ordinary temperature. One 
of the tubes that had been exposed to a temperature of 90° C. for one 
minute was kept over night and then tested with guaiacum. It gave 
only a faint blue coloration with this reagent. We see, therefore, that 
after destruction by heat these oxidases show but little if any tendency 
to regain their activity. In other words, the destruction by heat 
seems to be permanent. 
