After 24 hrs. the spherical or more commonly oblong masses of
protoplasm became opaque and granular, instead of being as usual
translucent; and in the lower cells there were only innumerable minute
spherical granules. It was evident that the strength of the solution
had interfered with the completion of the process, as we shall see
likewise follows from too great heat.
All the foregoing observations relate to the exterior tentacles, which
are of a purple colour; but the green pedicels of the short central
tentacles are acted on by the carbonate, and by an infusion of raw
meat, in exactly the same manner, with the sole difference that the
aggregated masses are of a greenish colour; so that the process is in
no way dependent on the colour of the fluid within the cells.
Finally, the most remarkable fact with respect to this salt is the
extraordinary small amount which suffices to cause aggregation. Full
details will be given in the seventh chapter, and here it will be
enough to say that with a sensitive leaf the absorption by a gland of
1/134400 of a grain (.000482 mgr.) is enough to cause in the course of
one hour well-marked aggregation in the cells immediately beneath the
gland.
The Effects of certain other Salts and Fluids. Two leaves were placed
in a solution of one part of acetate of ammonia to about [page 49] 146
of water, and were acted on quite as energetically, but perhaps not
quite so quickly, as by the carbonate. After 10 m. the glands were
black, and in the cells beneath them there were traces of aggregation,
which after 15 m. was well marked, extending down the tentacles for a
length equal to that of the glands. After 2 hrs. the contents of almost
all the cells in all the tentacles were broken up into masses of
protoplasm. A leaf was immersed in a solution of one part of oxalate of
ammonia to 146 of water; and after 24 m. some, but not a conspicuous,
change could be seen within the cells beneath the glands. After 47 m.
plenty of spherical masses of protoplasm were formed, and these
extended down the tentacles for about the length of the glands. This
salt, therefore, does not act so quickly as the carbonate. With respect
to the citrate of ammonia, a leaf was placed in a little solution of
the above strength, and there was not even a trace of aggregation in
the cells beneath the glands, until 56 m. had elapsed; but it was well
marked after 2 hrs. 20 m. On another occasion a leaf was placed in a
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