meat. After 3 hrs. 20 m. there was no change, but when next examined
after 23 hrs. 20 m., the outer cells of the glands contained, instead
of limpid fluid, spherical masses of a granular substance, showing that
matter had been absorbed from the infusion. That these glands secrete a
fluid which dissolves or digests animal matter out of the bodies of the
creatures which the leaves capture, is also highly probable from the
analogy of Dionaea. If we may trust to the same analogy, the concave
and inner portions of the two lobes probably close together by a slow
movement, as soon as the glands have absorbed a slight amount of [page
326] already soluble animal matter. The included water would thus be
pressed out, and the secretion consequently not be too much diluted to
act. With respect to the quadrifid processes on the outer parts of the
lobes, I was not able to decide whether they had been acted on by the
infusion; for the lining of protoplasm was somewhat shrunk before they
were immersed. Many of the points on the infolded rims also had their
lining of protoplasm similarly shrunk, and contained spherical granules
of hyaline matter.
A solution of urea was next employed. This substance was chosen partly
because it is absorbed by the quadrifid processes and more especially
by the glands of Utricularia a plant which, as we shall hereafter see,
feeds on decayed animal matter. As urea is one of the last products of
the chemical changes going on in the living body, it seems fitted to
represent the early stages of the decay of the dead body. I was also
led to try urea from a curious little fact mentioned by Prof. Cohn,
namely that when rather large crustaceans are caught between the
closing lobes, they are pressed so hard whilst making their escape that
they often void their sausage-shaped masses of excrement, which were
found within most of the leaves. These masses, no doubt, contain urea.
They would be left either on the broad outer surfaces of the lobes
where the quadrifids are situated, or within the closed concavity. In
the latter case, water charged with excrementitious and decaying matter
would be slowly forced outwards, and would bathe the quadrifids, if I
am right in believing that the concave lobes contract after a time like
those of Dionaea. Foul water would also be apt to ooze out at all
times, especially when bubbles of air were generated within the
concavity.
A leaf was cut open and examined, and the outer [page 327] cells of the
glands were found to contain only limpid fluid. Some of the quadrifids
283