188 VEGETABLE PHYSIOLOGY 
gmall bladder-like bodies, each with a small opening at its 
apex. This orifice is guarded by a number of stiff tapering 
bristles, and is closed by a sort of trapdoor which opens 
inwards and shuts again with a kind of spring. A small 
animal such as an aquatic insect can easily open it by press- 
ing against it, and thus can enter the bladder. The trapdoor 
immediately closes by virtue of its own elasticity, and 
cannot be opened by pressure from within. The insect 
Fic. 92.—Traps or Utricularia neglecta. (After Kerneyr.) 
a, a bladder magnified (x 4); b, section of a bladder ; c, absorption-cells 
on the internal surface of the bladder (x 250). 
accordingly finds egress impossible, and after a short 
time, usually ranging from one to three days, it perishes 
and its body decays, yielding to the plant the products 
of its decomposition, which are absorbed by particular 
cells growing from the internal wall of the bladder (fig. 92). 
Some of the so-called pitcher-plants show a somewhat 
similar mechanism and utilise corresponding organic sub- 
