Sulphate of Quinine.—Some of this salt was added to water, which is said to dissolve 1/1000 part of its weight. Five leaves were immersed, each in thirty minims of this solution, which tasted bitter. In less than 1 hr. some of them had a few tentacles inflected. In 3 hrs. most of the glands became whitish, others dark-coloured, and many oddly mottled. After 6 hrs. two of the leaves had a good many tentacles inflected, but this very moderate degree of inflection never increased. One of the leaves was taken out of the solution after 4 hrs., and placed in water; by the next morning some few of the inflected tentacles had re-expanded, showing that they were not dead; but the glands were still much discoloured. Another leaf not included in the above lot, after an immersion of 3 hrs. 15 m., was carefully examined; the protoplasm in the cells of the outer tentacles, and of the short green ones on the disc, had become strongly aggregated down to their bases; and I distinctly saw that the little masses changed their positions and shapes rather rapidly; some coalescing and again separating. I was surprised at this fact, because quinine is said to arrest all movement in the white corpuscles of the blood; but as, according to Binz,* this is due to their being no longer supplied with oxygen by the red corpuscles, any such arrestment of movement could not be expected in Drosera. That the glands had absorbed some of the salt was evident from their change of colour; but I at first thought that the solution might not have travelled down the cells of the tentacles, where the protoplasm was seen in active movement. This view, however, I have no doubt, is erroneous, for a leaf which had been immersed for 3 hrs. in the quinine solution was then placed in a little solution of one part of carbonate of ammonia to 218 of water; and in 30 m. the glands and the upper cells of the tentacles became intensely black, with the protoplasm presenting a very unusual appearance; for it * ‘Quarterly Journal of Microscopical Science,’ April 1874, p. 185. [page 202] had become aggregated into reticulated dingy-coloured masses, having rounded and angular interspaces. As I have never seen this effect produced by the carbonate of ammonia alone, it must be attributed to the previous action of the quinine. These reticulated masses were watched for some time, but did not change their forms; so that the protoplasm no doubt had been killed by the combined action of the two salts, though exposed to them for only a short time. Another leaf, after an immersion for 24 hrs. in the quinine solution, became somewhat flaccid, and the protoplasm in all the cells was aggregated. Many of the aggregated masses were discoloured, and presented a granular appearance; they were spherical, or elongated, or still more commonly consisted of little curved chains of small globules. None of these masses exhibited the least movement, and no doubt were all dead.