morning they were rather shrivelled, and many of the glands had fallen
off the tentacles. Drops of this acid were placed on the discs of four
leaves; in 40 m. all the tentacles were greatly inflected, excepting
the extreme marginal ones; and many of these after 3 hrs. became
inflected. I was led to try this acid from supposing that it was
present (which does not seem to be the case)* in olive oil, the action
of which is anomalous. Thus drops of this oil placed on the disc do not
cause the outer tentacles to be inflected; yet when minute drops were
added to the secretion surrounding the glands of the outer tentacles,
these were occasionally, but by no means always, inflected. Two leaves
were also immersed in this oil, and there
* See articles on Glycerine and Oleic Acid in Watts Dict. of
Chemistry. [page 193]
was no inflection for about 12 hrs.; but after 23 hrs. almost all the
tentacles were inflected. Three leaves were likewise immersed in
unboiled linseed oil, and soon became somewhat, and in 3 hrs. greatly,
inflected. After 1 hr. the secretion round the glands was coloured
pink. I infer from this latter fact that the power of linseed oil to
cause inflection cannot be attributed to the albumin which it is said
to contain.
Carbolic Acid. Two leaves were immersed in sixty minims of a solution
of 1 gr. to 437 of water; in 7 hrs. one was slightly, and in 24 hrs.
both were closely, inflected, with a surprising amount of mucus
secreted. These leaves were washed and left for two days in water; they
remained inflected; most of their glands became pale, and they seemed
dead. This acid is poisonous, but does not act nearly so rapidly or
powerfully as might have been expected from its known destructive power
on the lowest organisms. Half-minims of the same solution were placed
on the discs of three leaves; after 24 hrs. no inflection of the outer
tentacles ensued, and when bits of meat were given them, they became
fairly well inflected. Again half-minims of a stronger solution, of one
part to 218 of water, were placed on the discs of three leaves; no
inflection of the outer tentacles ensued; bits of meat were then given
as before; one leaf alone became well inflected, the discal glands of
the other two appearing much injured and dry. We thus see that the
glands of the discs, after absorbing this acid, rarely transmit any
174