640 PHARMACEUTICAL BOTANY 
Small animals, including crustaceans like Cyclops and Daphna, 
as well as larvae of small insects and worms, enter the bladders 
either because they seek a sheltered harbor for a time from larger 
prey or because they expect to find food within the bladder. In 
entering they have to press upon the valve and push it back. As 
soon as they stop pressing upon the valve, the elastic character of 
the valve causes it to close by bringing it back on the under lip 
cushion. ‘The entrapped animals struggle to escape by pressing 
themselves against the valve, but their efforts are in vain, for it is 
impossible for the prisoners to force the valve outwardly over the 
. cushion, and they die in time either from starvation or suffoca- 
tion. Their bodies decompose and the water-soluble products of 
decay are absorbed by quadrifid cells lining the entire inner wall 
of the bladder. 
Tue BurreRrworts 4 
The Butterworts comprise an interesting group of flesh-eat- 
ing plants which are placed in the genus Pinguicula. About 40 
species exist of which probably the best known is Pinguicula vul- 
garts, a member of the Uftriculariacee. which occurs in bogs or 
other damp places generally in mountainous districts of northern 
North America and Europe. Each plant exhibits a root system 
of from about 5 to 16 short, submerged, unbranched roots from 
which arises a rosette of oblong-ovate, yellowish-green leaves, the 
younger central ones being concave and more or less erect, the 
older marginal ones being flat or convex with their lower surfaces 
resting upon the moist ground. From the center of the leaf 
rosette there arises a slender scape bearing a single flower of 
violet blue hue that is spurred in its corolla portion. 
Alike with other investigated species of Pinguicula, the leaves 
of this plant have somewhat upturned margins which give them 
the form of a broad trough, the upper surface of which is covered 
with a viscid secretion. Microscopical examination of this sur- 
face discloses 2 types of glands (excepting along the margin), the 
first being of toadstool shape and consisting of a cylindrical stalk 
bearing a disc-shaped head of 8 to 16 cells arranged radially, 
the second consisting of a shorter stalk bearing an 8-celled head. 
