180 SEMI-CENTENNIAL OF TORREY BOTANICAL CLUB 
three plants grow in a cluster with the bases of their stipes united 
(PL. I, FIGS. I, 2; PL. 2, FIG. 9). The odor of this plant is like that 
of the commercial mushroom but the two plants could never be 
mistaken for each other. 
I have studied the effect of infusions of this fungus (I) on 
guinea pigs and rabbits when injected into or fed to these animals; 
(ID) on the heart-beat and blood-pressure of a cat; (III) on a 
skeletal muscle such as the gastrocnemius of the frog, and finally 
(IV) on the sciatic and vagus nerves of the frog. 
MATERIAL 
While Panaeolus venenosus grew rather abundantly in the 
mushroom beds where I made my collections, no great bulk of 
it could be obtained at any one time. The largest quantity I 
collected at any one time weighed from twenty-five to forty grams. 
I have as yet made no attempt to isolate the toxic element of the 
fungus in a pure state, but its common occurrence in commercial 
mushroom beds makes a knowledge of the general physiological 
effects highly desirable from a practical point of view. It is also 
of much interest to compare its physiological effects with those of 
the other well-known types of poisonous fungi. With two excep- 
tions (extracts Nos. 5 and 6) I used for my experiments infusions 
of this plant and the different infusions listed below give some idea 
of the amount of material available and the relative toxicity to be 
expected of the plants, so far as their juices are concerned. The 
plants collected were brought to the laboratory where they were 
washed in tap water to remove the soil particles and rinsed in dis- 
tilled water. They were then dried by applying filter paper to 
them and after that they were weighed and the juices were ex- 
ressed. 
Infusion No. 1 was made by macerating 25 gm. of Panaeolus 
venenosus in 25 c.c. of distilled water. The filtrate was diluted 
with sufficient water to make up 25 c.c. of fluid. The filtrate was 
yellowish orange in color at first but after standing for four hours 
its color changed to dark brown. 
Infusion No. 2 consisted of the juices of 25 gm. of P. venenosus 
ground with sand in a mortar to which 75 c.c. of distilled water 
had been added. The filtrate from the entire mass was used 
