INSECTIVOROUS PLANTS 209 
a pursuer, or perhaps out of pure curiosity, swims down 
the lane, guided by the bristles, and pushes against the 
trap-door. It lifts up easily, and our water-flea gets 
inside. But the valve shuts again by its own elasticity, 
and the edge rests against a cushion on the inner wall 
of the bladder. ‘Now the visitor finds that the trap-door 
opens only one way, and swims about, trying to find 
another opening. There is no other, and the valve shuts 
so close upon the cushion that he can get no leverage to 
prise it open. In there he stays until, in a day or two, 
he dies, either from starvation or because the water, 
rendered foul by the lack of air dissolved in it, slowly 
suffocates him; and his corpse, with those of others who 
have joined him, or whom he found there when he arrived, 
is slowly digested within this tiny stomach of the plant. 
The Pitcher-plants one often used to hear of as a 
special provision of Providence for the sustenance of 
thirsty travellers in the desert, providing in their leaves 
a draught of refreshing water for the exhausted voyager. 
That they are a most wonderful device of Providence is 
true enough, but it was not in the traveller’s interest, but 
in the plant’s. In the first place, they are almost always 
to be found in spots where there is water already, and in 
the second, no traveller would want to drink from the 
leaves, for they are half-full of rotting insects, and the 
whole thing smells abominably, and looks like liquid 
manure. JI cannot go into all the ingenious details 
here, for my business is with British plants, but the 
general principle is much the same in all. The pitcher- 
shaped leaves secrete honey along a line which leads to 
a precipice, and, once down, projecting hairs and other 
fortifications make the insect pretty sure of never coming 
back. 
P 
