solution, not then responding to a strong electrical current. On the
other hand, the movements of the cilia on the mantle of an Unio were
not always arrested, even when left for a consider-
* Proceedings of Royal Society, Feb. 18, 1875. [page 209]
able time in a very strong solution. On the whole, it seems that the
poison of the cobra acts far more injuriously on the protoplasm of the
higher animals than on that of Drosera.
There is one other point which may be noticed. I have occasionally
observed that the drops of secretion round the glands were rendered
somewhat turbid by certain solutions, and more especially by some
acids, a film being formed on the surfaces of the drops; but I never
saw this effect produced in so conspicuous a manner as by the cobra
poison. When the stronger solution was employed, the drops appeared in
10 m. like little white rounded clouds. After 48 hrs. the secretion was
changed into threads and sheets of a membranous substance, including
minute granules of various sizes.
Camphor. Some scraped camphor was left for a day in a bottle with
distilled water, and then filtered. A solution thus made is said to
contain 1/1000 of its weight of camphor; it smelt and tasted of this
substance. Ten leaves were immersed in this solution; after 15 m. five
of them were well inflected, two showing a first trace of movement in
11 m. and 12 m.; the sixth leaf did not begin to move until 15 m. had
elapsed, but was fairly well inflected in 17 m. and quite closed in 24
m.; the seventh began to move in 17 m., and was completely shut in 26
m. The eighth, ninth, and tenth leaves were old and of a very dark red
colour, and these were not inflected after an immersion of 24 hrs.; so
that in making experiments with camphor it is necessary to avoid such
leaves. Some of these leaves, on being left in the solution for 4 hrs.,
became of a rather dingy pink colour, and secreted much mucus; although
their tentacles were closely inflected, the protoplasm within the cells
was not at all aggregated. On another occasion, however, after a longer
immersion of 24 hrs., there was well marked aggregation. A solution
made by adding two drops of camphorated spirits to an ounce of water
did not act on one leaf; whereas thirty minims added to an ounce of
water acted on two leaves immersed together.
190