usual waved about, in water at 120 , and the tentacles became inflected
in from 2 m. to 3 m., but only so as to stand at right angles to the
disc. The leaf was now placed in the same solution (viz. one part of
carbonate of ammonia to 109 of water, or 4 grs. to 1 oz., which I will
for the future designate as the strong solution), and when I looked at
it again after the interval of an hour, the glands were blackened, and
there was well-marked aggregation. After an additional interval of 4
hrs. the tentacles had become much more inflected. It deserves notice
that a solution as strong as this never causes inflection in ordinary
cases. Lastly a leaf was suddenly placed in water at 125 (51 .6
Cent.), and was left in it until the water cooled; the tentacles were
rendered of a bright red and soon became inflected. The contents of the
cells underwent some degree of aggregation, which in the course of
three hours increased; but the masses of protoplasm did not become
spherical, as almost always occurs with leaves immersed in a solution
of carbonate of ammonia.]
We learn from these cases that a temperature of from 120 to 125
(48 .8 to 51 .6 Cent.) excites the tentacles into quick movement, but
does not kill the leaves, as shown either by their subsequent
re-expansion or by the aggregation of the protoplasm. We shall now see
that a temperature of 130 (54 .4 Cent.) is too high to cause immediate
inflection, yet does not kill the leaves.
[Experiment 1. A leaf was plunged, and as in all cases waved about for
a few minutes, in water at 130 (54 .4 Cent.), but there was no trace
of inflection; it was then placed in cold water, and after an interval
of 15 m. very slow movement was [page 70] distinctly seen in a small
mass of protoplasm in one of the cells of a tentacle.* After a few
hours all the tentacles and the blade became inflected.
Experiment 2. Another leaf was plunged into water at 130o to 131o, and
as before there was no inflection. After being kept in cold water for
an hour, it was placed in the strong solution of ammonia, and in the
course of 55 m. the tentacles were considerably inflected. The glands,
which before had been rendered of a brighter red, were now blackened.
The protoplasm in the cells of the tentacles was distinctly aggregated;
but the spheres were much smaller than those generated in unheated
leaves when subjected to carbonate of ammonia. After an additional 2
hrs. all the tentacles, excepting six or seven, were closely inflected.
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