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Show 200 DROSERA ROTUNDIFOLIA. CHAP. IX. were excited after an interval of a quarter to three quarters of an hour, by being rubbed or given bits of meat. Similar drops of a solution of one part to 218 of water (2 grs. to 1 oz.) quickly blackened the glands; some fe;v tent9.cles thus treat~d moved, whilst others did not. The latter, however, on bemg subsequently moistened with saliva or given bits of meat, became incurved thouo-h with extreme slowness; and this shows that J 0 . they had been injured. Stronger Rolutwns (but the strength was not ascertained) sometimes arrested all power of movement very quickly; thus bits of meat were placed on tho glands of several exterior tentacles, and as soon as they began to move, 1ninute drops of the strong solution were f1dded. They continued for a short time to go on bending, and then suddenly stood still; other tentacles on the same leaves, with meat on their glands, but not wetted with the strychnine, continued to bend and soon reached the centre of the leaf. Citrate of Strychnine.-Half-minims of a solution of one part to 437 of water were placed on the discs of six leaves; after 24 hrs. the outer tentacles showed only a trace of inflection. Bits of meat were then placed on three of these leaves, but in 24 hrs. only slight and irregular inflection occurred, proving that the leaves had been greatly injured. Two of the leaves to which meat had not been given had their discal glands dry and 1nuch injured. Minute drops of a strong solution of one part to 109 of water (4 grs. to 1 oz.) were added to the secretion round several glands, but did not produce nearly so plain an effect as the drops of a much weaker solution of the acetate. Particles of the dry citrate were placed on six glands; two of those moved some way towards the centre, and then stood still, being no doubt killed ; three others curved much farther inwards, and were then fixed; one alone reached the centre. Five leaves were immersed, each in thirty minims of a solution of one part to 437 of water; so that each received -(6 of a grain; after about 1 hr. some of the outer tentacles became inflected, and the glands were oddly mottled with black and white. These glands, in from 4 hrs. to 5 hrs., became whitish and opaque, and the protoplasm in the cells of the tentacles was well aggregated. By this time two of the leaves were greatly inflected, but the three others not much more inflected than they were before. Nevertheless two fresh leaves, after an immersion respectively for 2 hrs. and 4 hrs. in the solution, were not killed; for on being left for 1 hr. 30m. in a solution of one part of carbon-ate of ammonia to 218 of water, their tentacles became more inflected, and there was much aggregation. The glands CHAP. IX. ALKALOID I OISONS. 201 of two other leaves, after an immersion for 2 hrs. in a stronO'er solution, of one part of the citrate to 218 of water, became of an opaque, pale pink colour, which before long eli appoare l, leaving them: white.. One of these two leaves had its blade and tentacles greatly inflected; tho other hardly at all; but tho protoplasm in the cells of both was agoTegated down to the bases of the tentacles, with the spherical masses in tho cells close beneath the glands blackened. After 24 hrs. one of these leaves was colourless, and evidently dead. Sulphate of Quinine.-Somo of this sltlt was added to water, which is said to dissolve 10 1 00 part of its weight. Five leaves wore immersed, each in thirty minims of this solution, which tasted bitter. In loss 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. 15m., 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 clown 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 0 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 bec·ame intensely black, with the protoplasm presenting a very unusual appearance; for it * 'Quarterly Journal of Microscopical Science,' April 1874, p. 185. |