leaves all the tentacles on one side, but not those on the opposite
side, were inflected. I doubt whether this extremely unequal action can
be explained by supposing that the more active glands absorb all the
vapour as quickly as it is generated, so that none is left for the
others, for we shall meet with [page 143] analogous cases with air
thoroughly permeated with the vapours of chloroform and ether.
Minute particles of the carbonate were added to the secretion
surrounding several glands. These instantly became black and secreted
copiously; but, except in two instances, when extremely minute
particles were given, there was no inflection. This result is analogous
to that which follows from the immersion of leaves in a strong solution
of one part of the carbonate to 109, or 146, or even 218 of water, for
the leaves are then paralysed and no inflection ensues, though the
glands are blackened, and the protoplasm in the cells of the tentacles
undergoes strong aggregation.
[We will now turn to the effects of solutions of the carbonate.
Half-minims of a solution of one part to 437 of water were placed on
the discs of twelve leaves; so that each received 1/960 of a grain or
.0675 mg. Ten of these had their tentacles well inflected; the blades
of some being also much curved inwards. In two cases several of the
exterior tentacles were inflected in 35 m.; but the movement was
generally slower. These ten leaves re-expanded in periods varying
between 21 hrs. and 45 hrs., but in one case not until 67 hrs. had
elapsed; so that they re-expanded much more quickly than leaves which
have caught insects.
The same-sized drops of a solution of one part to 875 of water were
placed on the discs of eleven leaves; six remained quite unaffected,
whilst five had from three to six or eight of their exterior tentacles
inflected; but this degree of movement can hardly be considered as
trustworthy. Each of these leaves received 1/1920 of a grain (.0337
mg.), distributed between the glands of the disc, but this was too
small an amount to produce any decided effect on the exterior
tentacles, the glands of which had not themselves received any of the
salt.
Minute drops on the head of a small pin, of a solution of one part of
the carbonate to 218 of water, were next tried in the manner above
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