ammonia and an infusion of raw meat. As the glands of the Mirabilis
contain protoplasm, which did not become aggregated from exposure to
the fluids just named, though the contents of the cells in the blade of
the leaf were greatly affected by carbonate of ammonia, we may infer
that they cannot absorb. We may further infer that the innumerable
insects caught by this plant are of no more service to it than are
those which adhere to the deciduous and sticky scales of the leaf-buds
of the horse-chestnut.
The most interesting case for us is that of the two species of
Saxifraga, as this genus is distantly allied to Drosera. Their glands
absorb matter from an infusion of raw meat, from solutions of the
nitrate and carbonate of ammonia, and apparently from decayed insects.
This was shown by the changed dull purple colour of the protoplasm
within the cells of the glands, by its state of aggregation, and
apparently by its more rapid spontaneous movements.
* Comptes rendus, June 15, 1874. A good abstract of this paper is
given in the Gardener s Chronicle, July 11, 1874. [page 354]
The aggregating process spreads from the glands down the pedicels of
the hairs; and we may assume that any matter which is absorbed
ultimately reaches the tissues of the plant. On the other hand, the
process travels up the hairs whenever a surface is cut and exposed to a
solution of the carbonate of ammonia.
The glands on the flower-stalks and leaves of Primula sinensis quickly
absorb a solution of the carbonate of ammonia, and the protoplasm which
they contain becomes aggregated. The process was seen in some cases to
travel from the glands into the upper cells of the pedicels. Exposure
for 10 m. to the vapour of this salt likewise induced aggregation. When
leaves were left from 6 hrs. to 7 hrs. in a strong solution, or were
long exposed to the vapour, the little masses of protoplasm became
disintegrated, brown, and granular, and were apparently killed. An
infusion of raw meat produced no effect on the glands.
The limpid contents of the glands of Pelargonium zonale became cloudy
and granular in from 3 m. to 5 m. when they were immersed in a weak
solution of the carbonate of ammonia; and in the course of 1 hr.
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