Chap. IV.] THE EFFECTS OP HEAT. 69 



into quick movement, but does not kill the leaves, as shown 

 either by their subsequent re-expansion or by the aggregation 

 of the protoplasm. We shall now see that a temperature of 

 130 (54.4 Cent.) is too high to cause immediate inflection, 

 yet does not kill the leaves. 



Experiment 1. A leaf was plunged, and as in all cases waved 

 about for a few minutes, in water at 130 (54'*.4 Cent.), but there 

 was no trace of inflection; it was then placed in cold water, and 

 after an interval of 15 m. very slow movement was 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. 



Experiment 2. Another leaf was plunged into water at 130' to 

 131", and, as before, there was no inflection. After being kept in 

 cold water for an hour, it was placed in the strong solution of am- 

 monia, 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 ten- 

 tacles was distinctly aggr^ated ; 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 in- 

 flection. 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 inflec- 

 tion ; it was then placed in cold water, and after 1 hr. 20 m. some of 

 the tentacles on one side became inflected. This leaf was now placed 

 in the 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 inflectetl, with their cells exhibiting a slight degree of aggre- 

 gation; 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 145" (fl2".7 Cent.); neither be- 

 came inflectetl. One of these, however, after having been left for 31 

 m. in cold water, exhibited some slight inflection, which increased 

 after an additional interval of 1 hr. 45 m., until all the tentacles, ex- 



* Sacbs Btnten (' Tralt<' de Bo- after the.v were exposed for 1 m. 



tnnlqiie," 1784, p. STw) that the in water to a temperature of 47* 



movements -of the protoplasm In to 48* Cent., or 117' to 119 Fabr. 

 the balrs of a Cucurblta ceased 



