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Show 70 DROSERA ROTUNDIFOLIA. CHAP. IV. distinctly seen in a small mass of protoplasm in one of the cells of a tentacle."' After a few hours all the tentacles and the blade became inflected. Expr:riment 2.-Another leaf was plunged into water at 130° to 131 o and as before there was no inflection. After being kept in cold' water for an hour, it was placed in the strong solution of ammonia, and in the course of 55 m. the tentacles were considerably inflected. The glands, which before had been rendered of a brighter red, were now blackened. The protoplasm in the cells of the tentacles was distinctly aggregated; but the spheres were much smaller than those usually generated in unheated leaves when subjected to carbonate of ammonia. After an additional 2 hrs. all the tentacles, excepting six or seven, were closely inflected. Experiment 3.-A similar experiment to the last, with exactly the same results. Experiment 4.-A fine leaf was placed in water at 100° (37° · 7 Cent.), which was then raised to 145° (62°·7 Cent.). Soon after immersion, there was, as might have been expected, strong inflection. The leaf was now removed and left in cold water· but from having been exposed to so high a temperature, it' never re-expanded. Experiment 5.-Leaf immersed at 130° (54°·4 Cent.), and the water raised to 145° (62°'7 Cent.), there was no immediate inflection; it was then placed in cold water, and after 1 hr. 20m. some of the tentacles on one side became inflected. This leaf was now placed in ~he strong solution, and in 40 m. all the submarginal tentacles were well inflected, and the glands blackened. After an additional interval of 2 hrs. 45 m. all the tentacles, except eight or ten, were closely inflected, with their cells exhibiting a slight degree of aggregation; but the spheres of protoplasm were very small, and the cells of the exterior tentacles contained some pulpy or disintegrated brownish matter. Experiments 6 and 7.-Two leaves were plunged in water at 135° (57~·2 Cent.) which was raised to 14.5° (62°·7 Cent.); neither became m~ected. One of these, however, after having been left ~or 31 m. In cold water, exhibited some slight inflection which Increased after an additional interval of 1 hr. 45 m'.., until *. Sac~1s states (' Traite de Botamque, 1874, p. 85fl) that the movem~nts of the protoplasm in the hans of a Cucurbita oeased ~fter they were exposed for 1 m. m water to a temperature of 47° to 48° Cent., or 117° to 11D0 Fahr. CHAP. IV. THE EFFECTS OF HEAT. 71 ·all the tentacles, except sixteen or seventeen, were more or less inflected; but the leaf was so much injured that it never reexpanded. The other leaf, after having been left for half an hour in cold water, was put into the strong solution, but no inflection ensued; the glands, however, were blackened, and in some cells there was a little aggregation, the spheres of protoplasm being extremely small; in other cells, especially in the exterior tentacles, there was much greenish-brown pulpy matter. Experiment 8.-A leaf was plunged and waved about for a few minutes in water at 140° (60° Cent.), and was then left for half an hour in cold water, but there was no inflection. It was now placed in the strong solution, and after 2 hrs. 30 m. the inner submarginal tentacles were well inflected, with their glands blackened, and some imperfect aggregation in the cells of the pedicels. Three or four of the glands were spotted with the white porcelain-like structure, like that produced by boiling water. I have seen this result in no other instance after an immersion of only a few minutes in water at so low a temperature as 140°, and in only one leaf out of four, after a similar immersion at a temperature of 145° Fahr. On the other hand, with two leaves, one placed in water at 145° (62°·7 Cent.), and the other in water at 140° (60° Cent.), both being left therein until the water cooled, the glands of both became white and porcelain-like. So that the duration of the immersion is an important element in the result. Experiment 9.-A leaf was placed in water at 140° (60° Cent.), which was raised to 150° (65° · 5 Cent.); there was no inflection ; on the contrary, the outer tentacles were somewhat bowed backwards. The glands became like porcelain, but some of them were a little mottled with purple. The bases of the glands were often more affected than their summits. This leaf having been. left in the strong solution did not undergo any inflection or aggregation. Experiment 10.-A leaf was plunged in water at 150° to 150~ 0 (65° · 5 Cent.); it became somewhat flaccid, with the outer tentacles slightly reflexed, and the inner ones a little bent inwards, but only towards their tips; and this latter fact shows that the movement was not one of true inflection, as the basal part alone normally bends. The tentacles were as usual rendered of a very bright red, with the glands almost white like porcelain, yet tinged with pink. The leaf having been placed in the strong solution, the cell-contents of the tentacles became of a muddy brown, with ~o trace of aggregation. |