I may here add, in order not to recur to the papillae, that they do not
secrete, but are easily permeated by various fluids: thus when living
or dead leaves are immersed in a solution of one part of chloride of
gold, or of nitrate of silver, to 437 of water, they are quickly
blackened, and the discoloration soon spreads to the surrounding
tissue. The long multicellular hairs are not so quickly affected. After
a leaf had been left in a weak infusion of raw meat for 10 hours, the
cells of the papillae had evidently absorbed animal matter, for instead
of limpid fluid they now contained small aggregated masses of
protoplasm, which slowly and incessantly changed their forms. A similar
result followed from an immersion of only 15 minutes in a solution of
one part of carbonate of ammonia to 218 of water, and the adjoining
cells of the tentacles, on which the papillae were seated, now likewise
contained aggregated masses of protoplasm. We may therefore conclude
that when a leaf has closely clasped a captured insect in the manner
immediately to be described, the papillae, which project from the upper
surface of the leaf and of the tentacles, probably absorb some of the
animal matter dissolved in the secretion; but this cannot be the case
with the papillae on the backs of the leaves or on the petioles.]

* Nitschke has elaborately described and figured these papillae, 'Bot.
Zeitung,' 1861, pp. 234, 253, 254. [page 9]

Preliminary Sketch of the Action of the several Parts, and of the
Manner in which Insects are
Captured.

If a small organic or inorganic object be placed on the glands in the
centre of a leaf, these transmit a motor impulse to the marginal
tentacles. The nearer ones are first affected and slowly bend towards