After an immersion of 48 hrs. they were again examined, and their movements were so plain that they could easily be seen under a weak power. The leaves were now placed in water, and after 24 hrs. (i.e. 72 hrs. from their first immersion) the little masses of protoplasm, which had become of a dingy purple, were still in strong movement, changing their shapes, coalescing, and again separating.
In 8 hrs. after these two leaves had been placed in water (i.e. in 56 hrs. after their immersion in the solution) they began to re-expand, and by the next morning were more expanded. After an additional day (i.e. on the fourth day after their immersion in the solution) they were largely, but not quite fully [page 208] expanded. The tentacles were now examined, and the aggregated masses were almost wholly redissolved; the cells being filled with homogeneous purple fluid, with the exception here and there of a single globular mass. We thus see how completely the protoplasm had escaped all injury from the poison. As the glands were soon rendered quite white, it occurred to me that their texture might have been modified in such a manner as to prevent the poison passing into the cells beneath, and consequently that the protoplasm within these cells had not been at all affected. Accordingly I placed another leaf, which had been immersed for 48 hrs. in the poison and afterwards for 24 hrs. in water, in a little solution of one part of carbonate of ammonia to 218 of water; in 30 m. the protoplasm in the cells beneath the glands became darker, and in the course of 24 hrs. the tentacles were filled down to their bases with dark-coloured spherical masses. Hence the glands had not lost their power of absorption, as far as the carbonate of ammonia is concerned.
From these facts it is manifest that the poison of the cobra, though so deadly to animals, is not at all poisonous to Drosera; yet it causes strong and rapid inflection of the tentacles, and soon discharges all colour from the glands. It seems even to act as a stimulant to the protoplasm, for after considerable experience in observing the movements of this substance in Drosera, I have never seen it on any other occasion in so active a state. I was therefore anxious to learn how this poison affected animal protoplasm; and Dr. Fayrer was so kind as to make some observations for me, which he has since published.* Ciliated epithelium from the mouth of a frog was placed in a solution of .03 gramme to 4.6 cubic cm. of water; others being placed at the same time in pure water for comparison. The movements of the cilia in the solution seemed at first increased, but soon languished, and after 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.