Car. XIII SECRETION AND ABSORPTION. 299 
certain cases, this latte: stimulus is the more powerful 
of the two. Qn 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 im- 
possible that the leaves should be so differently af- 
fected by non-nitrogenous and nitrogenous bodies, and 
between these latter in a dry and damp condition. It 
is surprising how slightly damp a bit of meat or albu- 
men need be in order to excite secretion and afterwards 
slow movement, and equally surprising how minute a 
quantity of animal matter, when absorbed, 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 secrete, and 
afterwards the lobes to close. That the glands have 
the power of absorption is likewise shown by the very 
different lengths of time (as we shall presently see) 
during which the lobes remain closed over insects and 
other bodies yielding soluble nitrogenous matter, and 
over such as do not yield any: But there is direct 
evidence of absorption in the condition of the glands 
which have remained for some time in contact with 
animal matter. Thus bits of meat and crushed insects 
were several times placed on glands, and these were 
compared after some hours with other glands from 
distant parts of the same leaf. The latter showed 
not a trace of aggregation, whereas those which 
had been in contact with the animal matter were 
