9 
vations on the oxidases of this fungus have been made. In the first 
place, the earlier observations on the stability of the oxidases of this 
fungus have been confirmed. A 10 per cent aqueous extract of the 
fungus was prepared on August 17, 1904, and was found to be very 
active toward guaiacum. Some of this extract was kept in a glass- 
stoppered bottle in a dark closet at room temperature until January 2, 
1905, when it was again tested with guaiacum. With this reagent it 
gradually developed a dark-blue color, whereas a control experiment, 
in which some of the extract had been boiled previously, showed no 
blue color on testing with guaiacum. With the old solutions of the fun- 
gus the blue color with the fresh tincture of guaiacum develops more 
slowly than with the fresh extract of the fungus. A glycerin extract of 
the fungus was also found to retain its power of bluing guaiacum prac- 
tically unimpaired after four and one-half months. Such a glycerin 
extract was prepared on August 17 by macerating some of the fresh fun- 
gus with glycerin. At the time of its preparation this extract did not 
seem to possess quite as great oxidizing power as the aqueous extract. 
On January 2, 1905, a few drops of this glycerin extract were added 
to a small amount of water — about 1 cc. — and guaiacum added. In 
the course of a few moments it gave a deep indigo-blue color. From 
the facts as they are known at present it would seem that the oxidase 
of Lepiota americana is more stable in glycerin than in water. 
With the view of learning still more as to the stability of the oxi- 
dases of the higher fungi, a number of these plants indigenous to the 
District of Columbia have recently been examined for oxidases. 
Aqueous and glycerin extracts of a number of fungi were prepared as 
soon as the material was collected. The aqueous extract was filtered 
and tested for oxidases by means of tincture of guaiacum and tincture 
of aloin, with the following results: 
1 
2 
3 
4 
5 
6 
7 
8 
9 
10 
Name of fungus. 
Lactarius piperatus 
Russula emetica 
Lactarius volumen. . 
Volvaria bombycina 
Lactarius, indigo . . 
Clitocybe ochropurpurea 
Yellow fungus, undeter- 
mined. 
Small white variety, unde- 
termined. 
Agaricus campestris 
Amanita verna 
Color with guaiacum. 
Very dark blue instantly 
Dark blue 
Very dark blue instantly 
do 
Dark blue 
Very deep blue instantly 
do 
Light blue, slow 
Yellowish white 
Color with aloin. 
Wine red. 
Pink, slow. 
Wine red. 
Deep wine red. 
Do. 
Pink. 
Wine red. 
Do. 
Colorless. 
Do. 
It is evident from these results that of the fungi thus far examined 
b}^ far the greater number are rich in oxidases. The absence of oxi- 
dases from the highly poisonous mushroom Amanita verna is not 
19948— No. 26—06 2 
