OCR Text |
Show 212 DROSERA ROTUNDIFOLIA. CHAP. IX. three additional minutes. After 14m. an five leaves were well, and some of them closely, inflected. After 6 hrs. the glands were white and much mucus had been secreted. The leaves wore now flaccid, of a peculiar dull-red colour, and evidently dead. One of the leaves, after an immersion of 4 m., was brushed, like the ]eaves in the camphor, but this produced no effect. A plant with its roots in water was exposed under a 10-oz. vessel to the vapour of this oil, and in 1 hr. 20m. one leaf showed a trace of inflection. After 5 hrs. 20 m. the cover was taken off and the le:.tves examined; one bad all its tentacles closely inflected, the second about half in the same state; and the third all subinflected. 'rhe pl:.tnt was left in the open air for 42 hrs., but not a single tentacle expanded; all the glands appeared dead, except here and there one, which was still secreting. It is evident that this oil is highly exciting and poisonous to Drosera. Oil qf Gloves.-A mixture was made in the same manner as in the last case, and three leaves were immersed in it. After 30m. there was only a trace of inflection which never increased. After 1 hr. 30m. the glands were pale, and after 6 hrs. white. No doubt the leaves were much injured or killed. ~flurpentine.-Small drops placed on the discs of some leaves killed them, as did likewise drops of creosote. A plant was left for 15 m. under a 12-oz. vessel, with its inner surface wetted with twelve drops of turpentine; but no movement of the tentacles ensued. After 24 hrs. the plant was dead. (Jlycerine.-Half-minims were placed on the discs of three leaves: in 2 hrs. some of the outer tentacles were irregularly inflected; and in 19 Ius. the leaves were :flaccid and apparently dead; the glands which had touched the glycerine were colourless. :Minute drops (about -.lo of a minim) were applied to the glands of several tentacles, and in a few minutes these moved and soon reached the centre. Similar drops of a mixture of four dropped drops to 1 oz. of water were likewise applied to several glands; but only a few of the tentacles moved, and these very slowly and slightly. Half-minims of this same mixture placed on the discs of some leaves caused, to my surprise, no inflection in the course of 48 hrs. Bits of meat were then given them, and next day they were well inflected ; notwithstanding that some of the discal glands had been rendered almost colourless. 'l'wo leaves were immersed in the same mixture, but only for 4 hrs.; they were not inflected, and on being afterwards left for 2 hrs. 30m. in a solution r1 gr. to 1 oz.) of carbonate of ammonia, their glands were blackened, their tentacles inflected, and the protoplasm within their cells aggregated. It appears 0IIAP. IX. EFFECT OF PREVIOUS Uil\lERSION. ~13 from these facts that a mixture of four drop of glycerine to an o.uncc of water is 11ot poi onous, and excites very little in~ ectwn; ?ut that pure glycerine is poi. onou , and if applied In very mmutc quantities to tho glands of tho outer tentacles causes their inflection. Ti,e Effec;ts of l1nmersion in Water a11d in vu1·iou Solutions on the subsequent Action (!f Phosphate and Our·bonate of Ammon,:u.~ Ve ~a:e seen in the third and seventh chapters that immersion In distilled. water causes after a time some degree of aggregation o~ the. protoplasm, and a moderate amount of inflection, e peCI. ally In the case of plants which have been kept at a rather high temperature. Water docs not exrite a copious secretion of mucus. vVe have here to consider the effects of immersion in various fluids on the subsequent action of salts of ammonia, and other stimulants. Four leaves which had been left for 24 hrs. in water were given bits of meat, but did not clasp them. Ten lea vcs, after a similar immersion, were left for 24 hrs. in a po~erful solution (1 gr. to ~0 oz.) of phosphate of ammonia, and only one showed even a trace of inflection. Three of these leaves, on being left for an additional clay in the solution, still remained quite unaffected. When, however, sonte of the. e leaves, which had been first immersed in water for 24 hrs., and then in the phosphate for 24: hrs. were placed in a solution of carbonate of ammonia (one part to 218 of water), the protoplasm in the cells of the tentacles became in a few hotlrR strongly aggregated, showing that this salt had been absorbc<l and taken effect. A short immersion in water for 20 m. did not retard the subsequent action of the phosphate, or of splinters of glass placed on the glands; but in two instances an immersion for 50 m. prevented any eflect from a solution of camphor. Several leaves which had been left for 20m. in a solution of one part of white sugar to 218 of water were placed in the phosphate solution, the action of which was delayed; whereas a mixed solution of sugar and the phosphate did not in the least interfere with the effects of the latter. Three leaves, after being immersed for ~0 m. in the sugar solution, were placed in a solution of carbonate of ammonia (one part to 218 of water); in 2 m. or 3 m. the glands were blackened, and after 7 m. the tentacles were considerably inflected, so that the solution of sugar, though it delayed the action of the phosphate, did not delay that of the carbonate. Immersion in a similar solution of gum arabic for 20m. had no retarding action on the phosphate. Three leaves were left for 20 m. in a mixture of one part of alcohol to seven parts of water, |