between 15 and 20 minutes ceased; whilst those in the water were still acting vigorously.  The white corpuscles of the blood of a frog, and the cilia on two infusorial animals, a Paramaecium and Volvox, were similarly affected by the poison.  Dr. Fayrer also found that the muscle of a frog lost its irritability after an immersion of 20 m. in the 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.

M. Vogel has shown* that the flowers of various plants do not wither so soon when their stems are placed in a solution of camphor as when in water; and that if already slightly withered, they recover more quickly.  The germination of certain seeds is also accelerated by the solution.  So that camphor acts as a stimulant, and it is the only known stimulant for plants.  I