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Show 218 DROSERA ROTUNDIFOLIA. CHAP. IX. rendered for a time insensible to the action of raw meat, but sometimes are not thus affected, or in a very slight degree. A plant recovers from a small dose, but is easily killed by a larger one. A plant was left for 30 m. under a bell-glass holding 19 fluid oz. (539·6 mi.) with eight drops of chloroform, and before the cover was removed, most of the tentacles became much inflected, though they did not reach the centre. After the cover was removed, bits of meat were placed on the glands of several of the somewhat incurved tentaeles; these glands were found much blackened after 6 hrs. 30 m., but no further movement ensued. After 24 hrs. the leaves appeared almost dead. A smaller bell-glass, holding 12 fluid oz. (340·8 mi.), was now employed, and a plant was left for 90 s. under it, with only two drops of chloroform. Immediately on the removal of the glass all the tentacles curved inwards so as to stand perpendi? ularly up ; and some of them could actually be seen moving With extraordinary quickness by little starts, and therefore in an unnatural manner; but they never reached the centre. After 22 hrs. they fully re-expanded, and on meat being placed on their glands, or when roughly touched by a .needle, they promptly became inflected; so that these leaves had not been in the least injured. .Another plant was placed under the same smal(bell-glass With three drops of chloroform, and before two minutes had elapsed, the tentacles began to curl inwards with rapid little jerks. The glass was then removed, and in the course of two or three additional minutes almost every tentacle reached the centre. On several other occasions the vapour did not excite any movement of this kind. There seems also to be great variability in the degree and manner in which chloroform renders the glands insensible to the subsequent action of meat. In the plant last referred to, which had been exposed for 2 m. to three drops of chloroform, some few tentacles curved up only to a perpendicular position, and particles of meat were placed on their glands; this caused them in 5 m. to begin moving, but they moved so slowly that they did not reach the centre until 1 hr. 30 m. had elapsed. Another plant was similarly exposed, that is, for 2m. to three drops of chloroform, and on particles of meat being placed on the glands of several tentacles, which had curved up into a perpendicular position, one of these began to bend in 8 m., but afterwards moved very slowly; whilst none of the other tentacles CHAP. IX. VAPOUR OF ETHER. 219 moved for the next 40 m. Nevertheless, in 1 hr. 45 m. from the time when the bits of moat had been giv n, all the tentacles reached the centre. In this case some slight anmsthetic effect apparently had been produced. On the following day the plant had perfectly recovered. Another plant bearing two leaves was exposed for 2 m. under the 19-07;. vessel to two drops of chloroform; it was then taken out and examined; again exposed for 2 m. to two drops; taken out, and re-exposcd for 3 m. to three drops; so that altogether it was exposed alternately to the air and during 7 m. to the vapour of seven drops of chloroform. Bits of meat were now placed on thirteen glands on the two· leaves. On one of these leaves, a single tentacle first began moving in 40 m.t and two others in 54 m. On the second leaf sorp.e tentacles first moved in 1 hr. 11m. After 2 hrs. many tentacles on both leaves we1·e inflected; but none ha<l reached the centre within this time. In this case there could not be the least doubt that the chloroform had exerted an anmsthetic influence on the leaves. On the other hand, another plant was exposed under the same vessel for a much longer time, viz. 20m., to twice as much chloroform. Bits of meat were then placed on the glands of many tentacles, and all of them, with a single exception, reached the centre in from 13m. to 14m. In this case, little or no anresthetic effect had been produced; and how to reconcile these discordant results, I know not. Vapour of Sulphuric Ether.-A plant was ~xposed for 30 m .. to thirty minims of this ether in a vessel holdmg 19 oz.; a.nd bits of raw meat were afterwards placed on many glands which had become pale-coloured: but. none of the tentacles moved. After 6 hrs. 30 m. the leaves appeared sickly, and the discal glands were almost dry. By the next morning many of the tentacles were dead as were all those on which meat had been placed; showing that matter had been absorbed from the meat which had jncreased the evil effects of the vapour. After four days the plant itself died. Another plant was exposed in the same vessel for 15 m. to forty minims. One young, Rmall, and tender leaf had all its tentacles inflected, and seemed much injured. Bits of raw meat were placed on several glands. on two other and older leaves. These glands became dry after 6 hrs., and seemed injured; the tentacles never moved, except-. ing one which was ultimately a little inflected. The gl.a~ds of the other tentacles continued to secrete, and appeared umnJurcdJ but the whole plant after three days became very sickly. |