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Show 220 DROSERA ROTUNDIFOLIA. CnAP. IX. In the two foregoing experiments the doses were evidently too large and poisonous. With weaker doses, the anrosthetie effect was variable, as in the case of chloroform. A plant was exposed for 5 m. to ten drops under a 12-oz. vessel, and bits of meat were then placed on many glands. None of the tentacles thus treated began to move in a decided manner until 40 m. had elapsed; but then some of them moved very quickly, so that two reached the centre after an additional interval of only 10m. In 2 hrs. 12m. from the time when the meat was given, all the tentacles reached the centre. Another plant, with two leaves, was exposed in the same vessel for 5 m. to a rather larger close of ethAr, and bits of meat were placed on several glands. In this case one tentacle on each leaf began to bend in 5 m. ; and after 12 m. two tentacles on one leaf, and one on the second leaf, reached the centre. In 30m. after the meat had been given, all the tentacles, both those with and without meat, were closely inflected; so that the ether apparently had stimulated these leaves, causing all the tentacles to bend. Vapour of' Nitric Ether.-This vapour seems more injurious than that of sulphuric ether. A plant was exposed for 5 m. in a 12- oz. vessel to eight drops in a watch-glass, and I distinctly saw a few tentacles curling inwards before the glass was removed. Immediately afterwards bits of meat were placed on three glands, but no movement ensued in the course of 18m. The same plant was placed again under the same vessel for 16m. with ten drops of the ether. None of the tentacles moved, and next morning those with the meat were still in the same position. After 48 hrs. one leaf seemed healthy, but the others were much injured. Another plant, having two good leaves, was exposed for 6 m. under a 19-oz. vessel to the vapour from 1·en minims of the ether, and bits of meat were then placed on the glands of many tentacles on both leaves. After 36 m. several of then1 on one leaf became inflected, and after 1 hr. almost all the tentacles, those with and without meat, nearly reached the centre. On the other leaf the glands began to dry in 1 hr. 40 m., and after several hours not a single tentacle was inflected; but by the next morning, after 21 Ius., many were inflected, though they seemed much injured. In this and the previous experiment, it is doubtful, owing to the injury which the leaves had suffered, whether any anrosthetic effect had been produced. A third plant, having two good leaves, was exposed for only 4 m. in the 19-oz. vessel to the vapour from six drops. Bits of meat were then placed on the glands of seven tentacles on the CHAP. IX. CARBONIC ACID. 221 same loaf. A single tentacle moved after 1 hr. 23 m.; aft r 2 hrs. 3 m. several were inflected ; and after 3 hr . 3 m. all tho seven tentacles with moat wore well inflected. FTom the slowness of these movements it is clear that this leaf had been rendered insensible for a timo to tho action of the meat. A second leaf was rather differently affected; bits of meat wero placed on the glands of five tentacles, three of which were slightly inflected in 28 m.; after 1 hr. 21 m. one reached tho centre, but tho other two wore still only slightly inflected; after 3 hrs. they wore much more inflected; but even after 5 hrs. 16 m. all five had not roached the centre. Although some of the tentacles began to move moderately soon, they afterwards moved with extreme slowness. By next mornin()', nJter 20 Ill's., most of the tentacles on both leaves were closely inflected, but not quite regularly. After 48 brs. neither leaf appeared injured, though the tentacles were still .inflected ; after 72 brs. one was almost dead, whilst tho other was ro-expanding and recovering. Cc11'bonic .Acirl.-A plant was placed under a 122-oz. bell-glass filled with this gas and standing over water; but I did not make sufficient allowance for the absorption of tho gas by the water, so that towards the latter part of the experiment some ail' was drawn in. After an exposure of 2 hrs. the plant was removed, and bits of raw meat placed on the glands of three leaves. One of these leaves hung a little down, and was at first partly and soon afterwards completely covered by the water, which 1·ose within the vessel as tho gas was absorbed. On thjs latter leaf the tentacles, to which moat had been given, became well inflected in 2 m. 30 s., that is, at about the normal rate; so that until I remembered that the leaf had been protected from the gas, and might perhaps have absorbed oxygen from the watm· which was continually drawn inwards, I falsely concluded that the carbonic acid had produced no effect. On tho other two leaves, the tentacles with meat behaved very differently from those on the first leaf; two of them first began to move slightly in 1 hr. 50 m., always reckoning from tho time when the meat was placed on the glands-were plainly inflected in 2 hrs. 22 m.-ancl in 3 hrs 22 m. reached the centre. Three other tentacles did not begin to move until 2 hrs. 20 m. had elapsed, but reached the centre at about the same time with the others, viz. in 3 hrs. 22 m. This experiment was repeated several times with nearly the same results, excepting that the interval before the tentacles began to m9ve varied a little. I will give only one other case. |