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380 PINGUICULA VULGARIS. Car. XVI. 
Prof. Dyer, in most. or all the species of the genus, 
the edges of the leaves are in some degree naturally 
and permanently incurved. This incurvation serves, 
as already shown, to prevent insects from being 
washed away by the rain; but it likewise serves for 
another end. When a number of glands have been 
powerfully excited by bits of meat, insects, or any other 
stimulus, the secretion often trickles down the leaf, 
and is caught by the incurved edges, instead of rolling 
off and being lost. As it runs down the channel, fresh 
glands are able to absorb the animal matter held in 
solution. Moreover, the secretion often collects in 
little pools within the channel, or in the spoon-like 
tips of the leaves; and I ascertained that bits of albu- 
men, fibrin, and gluten, are here dissolved more 
quickly and completely than on the surface of the 
leaf, where the secretion cannot accumulate; and so 
it would be with naturally caught insects. The secre- 
tion was repeatedly seen thus to collect on the leaves 
of plants protected from the rain; and with exposed 
plants there would be still greater need of some pro- 
vision to prevent, as far as possible, the secretion, with 
its dissolved animal matter, being wholly lost. 
It has already been remarked that plants growing 
in a state of nature have the margins of their leaves 
much more strongly incurved than those grown in 
pots and prevented from catching many insects. We 
have seen that insects washed down by the rain from 
all parts of the leaf often lodge within the margins, 
which are thus excited to curl farther inwards; and 
we may suspect that this action, many times repeated 
during the life of the plant, leads to their permanent 
and well-marked incurvation. I regret that this view 
did not occur to me in time to test its truth. 
It may here be added, though not immediately 
