grs. to 1 oz.), and observed it under a high power. All the glands
began to
* Judging from an account of M. Heckel s observations, which I have
only just seen quoted in the Gardeners Chronicle (Oct. 10, 1874), he
appears to have observed a similar phenomenon in the stamens of
Berberis, after they have been excited by a touch and have moved; for
he says, the contents of each individual cell are collected together
in the centre of the cavity. [page 44]
darken in 10 s. (seconds); and in 13 s. were conspicuously darker. In 1
m. extremely small spherical masses of protoplasm could be seen arising
in the cells of the pedicels close beneath the glands, as well as in
the cushions on which the long-headed marginal glands rest. In several
cases the process travelled down the pedicels for a length twice or
thrice as great as that of the glands, in about 10 m. It was
interesting to observe the process momentarily arrested at each
transverse partition between two cells, and then to see the transparent
contents of the cell next below almost flashing into a cloudy mass. In
the lower part of the pedicels, the action proceeded slower, so that it
took about 20 m. before the cells halfway down the long marginal and
submarginal tentacles became aggregated.
We may infer that the carbonate of ammonia is absorbed by the glands,
not only from its action being so rapid, but from its effect being
somewhat different from that of other salts. As the glands, when
excited, secrete an acid belonging to the acetic series, the carbonate
is probably at once converted into a salt of this series; and we shall
presently see that the acetate of ammonia causes aggregation almost or
quite as energetically as does the carbonate. If a few drops of a
solution of one part of the carbonate to 437 of water (or 1 gr. to 1
oz.) be added to the purple fluid which exudes from crushed tentacles,
or to paper stained by being rubbed with them, the fluid and the paper
are changed into a pale dirty green. Nevertheless, some purple colour
could still be detected after 1 hr. 30 m. within the glands of a leaf
left in a solution of twice the above strength (viz. 2 grs. to 1 oz.);
and after 24 hrs. the cells of the pedicels close beneath the glands
still contained spheres of protoplasm of a fine purple tint. These
facts show that the ammonia had not entered as a carbonate, for
38