stronger solution, of one part of the citrate to 109 of water (4 grs.
to 1 oz.), and at the same time another leaf in a solution of the
carbonate of the same strength. The glands of the latter were blackened
in less than 2 m., and after 1 hr. 45 m. the aggregated masses, which
were spherical and very dark-coloured, extended down all the tentacles,
for between half and two-thirds of their lengths; whereas in the leaf
immersed in the citrate the glands, after 30 m., were of a dark red,
and the aggregated masses in the cells beneath them pink and elongated.
After 1 hr. 45 m. these masses extended down for only about one-fifth
or one-fourth of the length of the tentacles.
Two leaves were placed, each in ten minims of a solution of one part of
nitrate of ammonia to 5250 of water (1 gr. to 12 oz.), so that each
leaf received 1/576 of a grain (.1124 mgr.). This quantity caused all
the tentacles to be inflected, but after 24 hrs. there was only a trace
of aggregation. One of these same leaves was then placed in a weak
solution of the carbonate, and after 1 hr. 45 m. the tentacles for half
their lengths showed an astonishing degree of aggregation. Two other
leaves were then placed in a much stronger solution of one part of the
nitrate to 146 of water (3 grs. to 1 oz.); in one of these there was no
marked change after 3 hrs.; but in the other there was a trace of
aggregation after 52 m., and this was plainly marked after 1 hr. 22 m.,
but even after 2 hrs. 12 m. there was certainly not more aggregation
than would have fol- [page 50] lowed from an immersion of from 5 m. to
10 m. in an equally strong solution of the carbonate.
Lastly, a leaf was placed in thirty minims of a solution of one part of
phosphate of ammonia to 43,750 of water (1 gr. to 100 oz.), so that it
received 1/1600 of a grain (.04079 mgr.); this soon caused the
tentacles to be strongly inflected; and after 24 hrs. the contents of
the cells were aggregated into oval and irregularly globular masses,
with a conspicuous current of protoplasm flowing round the walls. But
after so long an interval aggregation would have ensued, whatever had
caused inflection.
Only a few other salts, besides those of ammonia, were tried in
relation to the process of aggregation. A leaf was placed in a solution
of one part of chloride of sodium to 218 of water, and after 1 hr. the
contents of the cells were aggregated into small, irregularly globular,
brownish masses; these after 2 hrs. were almost disintegrated and
44