Cuar. XIII.] SECRETION AND ABSORPTION. 241 
should have observed the leaves for a longer time, and they 
would probably have been found closed, though the solution 
(judging from Drosera) was, perhaps, too strong. 
From the foregoing cases it is certain that bits of meat 
and albumen, if at all damp, excite not only the glands to 
secrete, but the lobes to close. This movement is widely 
different from the rapid closure caused by one of the 
filaments being touched. We shall see its importance when 
we treat of the manner in which insects are captured. 
There is a great contrast between Drosera and Dionza in the 
effects produced by mechanical irritation on the one hand, 
and the absorption of animal matter on the other. Particles 
of glass placed on the glands of the exterior tentacles of 
Drosera excite movement within nearly the same time, as 
do particles of meat, the latter being rather the most 
efficient ; but when the glands of the disc have bits of meat 
given them, they transmit a motor impulse to the exterior 
tentacles much more quickly than do these glands when 
bearing inorganic particles, or when irritated by repeated 
touches. On the other hand, with Dionea, touching the 
filaments excites incomparably quicker movement than the 
absorption of animal matter by the glands. Nevertheless, in 
certain cases, this latter stimulus is the more powerful of the 
two. On three occasions leaves were found which from 
some cause were torpid, so that their lobes closed only 
slightly, however much their filaments were irritated ; but 
on inserting crushed insects between the lobes, they became 
in a day closely shut. 
The facts just given plainly show that the glands have 
the power of absorption, for otherwise it is impossible that 
the leaves should be so differently affected by non-nitro- 
genous and nitrogenous bodies, and between these latter in a 
dry and damp condition. It is surprising how slightly 
damp a bit of meat or albumen need be in order to excite 
secretion and afterwards slow movement, and equally 
surprising how minute a quantity of animal matter, when 
ubsorbed, suffices to produce these two effects. It seems 
hardly credible, and yet it is certainly a fact, that a bit of 
hard-boiled white of egg, first thoroughly dried, then soaked 
for some minutes in water and rolled on blotting-paper, 
should yield in a few hours enough animal matter to the 
glands to cause them to secret>, and afterwards the lobes to 
close. That the glands have the power of absorption is 
R 
