120 OCCASIONALLY FATAL. 
and found that by brushing it over his arm he produced 
effects similar to those of Poison Ivy. In fourteen hours 
his whole arm and hand were much swollen and badly 
inflamed. The swelling did not go down for ten days, 
and effects were felt for a month. 
The poison is in the form of a fatty acid, whose exact 
composition is not yet determined. It is contained in 
glandular hairs, which cover the surface of stem ahd 
leaves. The effect is strongest in the fruiting period. 
Even at this time, however, many more people are im- 
mune than in the case of Poison Ivy. 1 
The Cypripediums are showy plants with brightly 
coloured flowers. There are three sepals, coloured like 
the petals. Two of these are usually united beneath a 
large, sac-like lip (the “slipper” or ‘‘moccasin’’) formed 
by one of the petals. The other petals stand out at the 
sides. There are three stamens, one of which is strap- 
like and sterile. The other two, one on each side, have 
two-celled anthers with masses of granular pollen. The 
leaves are many-nerved and plaited, with a sheathing 
base. 
The following species are mentioned as: poisonous: 
The Smaller Yellow Lady-slipper, Cypripedium parvi- 
florum Salisb., is a species widely distributed in swampy 
woods and bogs. Stem six to sixteen inches high; petals 
and sepals greenish, suffused with madder purple, one to 
one and a half inches long. Lip yellow with purplish 
spots or lines. 
The Large Yellow Lady-slipper, Cypripedium pubes- 
cens Willd., somewhat larger and more hairy than the 
preceding, with a larger. lip less strongly marked with 
purple; often growing in clusters in low woods or on 
moist prairie. 
