* Dr. W.M. Canby, of Wilmington, to whom I am much indebted for
information regarding Dionaea in its native home, has published in the
‘Gardener’s Monthly,’ Philadelphia, August 1868, some interesting
observations. He ascertained that the secretion digests animal matter,
such as the contents of insects, bits of meat, &c.; and that the
secretion is reabsorbed. He was also well aware that the lobes remain
closed for a much longer time when in contact with animal matter than
when made to shut by a mere touch, or over objects not yielding soluble
nutriment; and that in these latter cases the glands do not secrete.
The Rev. Dr. Curtis first observed (‘Boston Journal Nat. Hist.’ vol.
i., p. 123) the secretion from the glands. I may here add that a
gardener, Mr. Knight, is said (Kirby and Spencer’s ‘Introduction to
Entomology,’ 1818, vol. i., p. 295) to have found that a plant of the
Dionaea, on the leaves of which “he laid fine filaments of raw beef,
was much more luxuriant in its growth than others not so treated.”
[page 302]
1/10 broad; the leaf was then made to close. It was cut open after 45
hrs. The albumen was hard and compressed, with its angles only a little
rounded; the gelatine was corroded into an oval form; and both were
bathed in so much acid secretion that it dropped off the leaf. The
digestive process apparently is rather slower than in Drosera, and this
agrees with the length of time during which the leaves remain closed
over digestible objects.
Experiment 2.—A bit of albumen 1/10 of an inch square, but only 1/20 in
thickness, and a piece of gelatine of the same size as before, were
placed on a leaf, which eight days afterwards was cut open. The surface
was bathed with slightly adhesive, very acid secretion, and the glands
were all in an aggregated condition. Not a vestige of the albumen or
gelatine was left. Similarly sized pieces were placed at the same time
on wet moss on the same pot, so that they were subjected to nearly
similar conditions; after eight days these were brown, decayed, and
matted with fibres of mould, but had not disappeared.
Experiment 3.—A piece of albumen 3/20 of an inch (3.81 mm.) long, and
1/20 broad and thick, and a piece of gelatine of the same size as
before, were placed on another leaf, which was cut open after seven
days; not a vestige of either substance was left, and only a moderate
amount of secretion on the surface.
Experiment 4.—Pieces of albumen and gelatine, of the same size as in
the last experiment, were placed on a leaf, which spontaneously opened
after twelve days, and here again not a vestige of either was left, and
only a little secretion at one end of the midrib.
Experiment 5.—Pieces of albumen and gelatine of the same size were
placed on another leaf, which after twelve days was still firmly
closed, but had begun to wither; it was cut open, and contained nothing
except a vestige of brown matter where the albumen had lain.
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