Cuar. XVI] SECRETION, ABSORPTION, DIGESTION. 307 
or in the spoon-like tips of the leaves; and I ascertained that 
bits of albumen, 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 secretion 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 provision 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 bearing on 
our subject, that when a plant is pulled up, the leaves 
immediately curl downwards so as to almost conceal the 
roots,—a fact which has been noticed by many persons. 
I suppose that this is due to the same tendency which causes 
the outer and older leaves to lie flat on the ground. It 
further appears that the flower-stalks are to a certain extent 
irritable, for Dr. Johnson states that they “bend backwards 
if rudely handled.” * 
Secretion, Absorption, and Digestion —I will first give my 
observations and experiments, and then a summary of the 
results. 
The Effects of Objects containing Soluble Nitrogenous Matter. 
(1) Flies were placed on many leaves, and excited the glands to 
secrete copiously; the secretion always becoming acid, though not so 
vefore. After a time these insects were rendered so tender that their 
imbs and bodies could be separated by a mere touch, owing no doubt 
* ‘English Botany,’ by Sir J. E. bending or shaking a turgescent stem. 
Smith; with coloured figures by J. This would be likely to occur in the 
Sowerby ; edit. of 1832, tab. 24, 25, course of the “rough handling,” and 
26. [It is well known that perma- we may perhaps thus account for 
nent curvatures may be produced by Dr, Johnson’s curvatures.—F, D,] 
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