Mercury, Perchloride of.—Three leaves were immersed in ninety minims of a solution of one part to 437 of water; after 22 m. there was some slight inflection, which in 48 m. became well pronounced; the glands were now blackened. After 5 hrs. 35 m. all the tentacles closely inflected; after 24 hrs. still [page 184] inflected and discoloured. The leaves were then removed and left for two days in water; but they never re-expanded, being evidently dead.
Zinc, Chloride of.—Three leaves immersed in ninety minims of a solution of one part to 437 of water were not affected in 25 hrs. 30 m.
Aluminium, Chloride of.—Four leaves were immersed in 120 minims of a solution of one part to 437 of water; after 7 hrs. 45 m. no inflection; after 24 hrs. one leaf rather closely, the second moderately, the third and fourth hardly at all, inflected. The evidence is doubtful, but I think some power in slowly causing inflection must be attributed to this salt. These leaves were then placed in the solution (1 gr. to 20 oz.) of phosphate of ammonia, and after 7 hrs. 30 m. the three, which had been but little affected by the chloride, became rather closely inflected.
Aluminium, Nitrate of.—Four leaves were immersed in 120 minims of a solution of one part to 437 of water; after 7 hrs. 45 m. there was only a trace of inflection; after 24 hrs. one leaf was moderately inflected. The evidence is here again doubtful, as in the case of the chloride of aluminium. The leaves were then transferred to the same solution, as before, of phosphate of ammonia; this produced hardly any effect in 7 hrs. 30 m.; but after 25 hrs. one leaf was pretty closely inflected, the three others very slightly, perhaps not more so than from water.
Aluminium and Potassium, Sulphate of (common alum).—Half-minims of a solution of the usual strength were placed on the discs of nine leaves, but produced no effect.
Gold, Chloride of.—Seven leaves were immersed in so much of a solution of one part to 437 of water that each received 30 minims, containing 1/16 of a grain, or 4.048 mg., of the chloride. There was some inflection in 8 m., which became extreme in 45 m. In 3 hrs. the surrounding fluid was coloured purple, and the glands were blackened. After 6 hrs. the leaves were transferred to water; next morning they were found discoloured and evidently killed. The secretion decomposes the chloride very readily; the glands themselves becoming coated with the thinnest layer of metallic gold, and particles float about on the surface of the surrounding fluid.
Lead, Chloride of.—Three leaves were immersed in ninety minims of a solution of one part to 437 of water. After 23 hrs. there was not a trace of inflection; the glands were not blackened, and the leaves did not appear injured. They were then trans- [page 185] ferred to the solution (1 gr. to 20 oz.) of phosphate of ammonia, and after 24 hrs. two of them were somewhat, the third very little, inflected; and they thus remained for another 24 hrs.
Tin, Chloride of.—Four leaves were immersed in 120 minims of a solution of about one part (all not being dissolved) to 437 of water. After 4 hrs. no effect; after 6 hrs. 30 m. all four leaves had their submarginal tentacles inflected; after 22 hrs. every single tentacle and the blades were closely inflected. The surrounding fluid was now coloured pink. The leaves were washed and transferred to water, but next morning were evidently dead. This chloride is a deadly poison, but acts slowly.
Antimony, Tartrate of.—Three leaves were immersed in ninety minims of a solution of one part to 437 of water. After 8 hrs. 30 m. there was slight inflection; after 24 hrs. two of the leaves were closely, and the third moderately, inflected; glands not much darkened. The leaves were washed and placed in water, but they remained in the same state for 48 additional hours. This salt is probably poisonous, but acts slowly.
Arsenious Acid.—A solution of one part to 437 of water; three leaves were immersed in ninety minims; in 25 m. considerable inflection; in 1 h. great inflection; glands not discoloured. After 6 hrs. the leaves were transferred to water; next morning they looked fresh, but after four days were pale-coloured, had not re-expanded, and were evidently dead.