(.001009 mg.) of the salt; and this quantity sufficed to induce within
a short time conspicuous aggregation in the cells beneath all the
glands.
A vigorous but rather small red leaf was placed in six minims of the
same solution (viz. one part to 5250 of water), so that it received
1/960 of a grain (.0675 mg.). In 40 m. the glands appeared rather
darker; and in 1 hr. from four to six spheres of protoplasm were formed
in the cells beneath the glands of all the tentacles. I did not count
the tentacles, but we may [page 147] safely assume that there were at
least 140; and if so, each gland could have received only the 1/134400
of a grain, or .00048 mg.
A weaker solution was then made of one part to 7000 of water, and four
leaves were immersed in it; but I will give only one case. A leaf was
placed in ten minims of this solution; after 1 hr. 37 m. the glands
became somewhat darker, and the cells beneath all of them now contained
many spheres of aggregated protoplasm. This leaf received 1/768 of a
grain, and bore 166 glands. Each gland could, therefore, have received
only 1/127488 of a grain (.00507 mg.) of the carbonate.
Two other experiments are worth giving. A leaf was immersed for 4 hrs.
15 m. in distilled water, and there was no aggregation; it was then
placed for 1 hr. 15 m. in a little solution of one part to 5250 of
water; and this excited well-marked aggregation and inflection. Another
leaf, after having been immersed for 21 hrs. 15 m. in distilled water,
had its glands blackened, but there was no aggregation in the cells
beneath them; it was then left in six minims of the same solution, and
in 1 hr. there was much aggregation in many of the tentacles; in 2 hrs.
all the tentacles (146 in number) were affected the aggregation
extending down for a length equal to half or the whole of the glands.
It is extremely improbable that these two leaves would have undergone
aggregation if they had been left for a little longer in the water,
namely for 1 hr. and 1 hr. 15 m., during which time they were immersed
in the solution; for the process of aggregation seems invariably to
supervene slowly and very gradually in water.]
A Summary of the Results with Carbonate of Ammonia. The roots absorb
the solution, as shown by their changed colour, and by the aggregation
of the contents of their cells. The vapour is absorbed by the glands;
128