tentacles on one leaf became considerably inflected; those with the
meat not in the least degree more than the others. On a second leaf,
which was rather old, the tentacles with meat, as well as a few others,
were moderately inflected. On a third leaf all the tentacles were
closely inflected, though meat had not been placed on any of the
glands. This movement, I presume, may be attributed to excitement from
the absorption of oxygen. The last-mentioned leaf, to which no meat had
been given, was fully re-expanded after 24 hrs.; whereas the two other
leaves had all their tentacles closely inflected over the bits of meat
which by this time had been carried to their centres. Thus these three
leaves had perfectly recovered from the effects of the gas in the
course of 24 hrs.
On another occasion some fine plants, after having been left for 2 hrs.
in the gas, were immediately given bits of meat in the usual manner,
and on their exposure to the air most of their tentacles became in 12
m. curved into a vertical or sub-vertical position, but in an extremely
irregular manner; some only on one side of the leaf and some on the
other. They remained in this position for some time; the tentacles with
the bits of meat not having at first moved more quickly or farther
inwards than the others without meat. But after 2 hrs. 20 m. the former
began to move, and steadily went on bending until they reached the
centre. Next morning, after 22 hrs., all the tentacles on these leaves
were closely clasped over the meat which had been carried to their
centres; whilst the vertical and sub-vertical tentacles on the other
leaves to which no meat had been given had fully re-expanded. Judging,
however, from the subsequent action of a weak solution of carbonate of
ammonia on one of these latter leaves, it had not perfectly recovered
its excitability and power of movement in 22 hrs.; but another leaf,
after an additional 24 hrs., had completely recovered, judging from the
manner in which it clasped a fly placed on its disc.
I will give only one other experiment. After the exposure of a plant
for 2 hrs. to the gas, one of its leaves was immersed in a rather
strong solution of carbonate of ammonia, together with [page 223] a
fresh leaf from another plant. The latter had most of its tentacles
strongly inflected within 30 m.; whereas the leaf which had been
exposed to the carbonic acid remained for 24 hrs. in the solution
without undergoing any inflection, with the exception of two tentacles.
This leaf had been almost completely paralysed, and was not able to
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