Cuar. IV.] THE EFFECTS OF HEAT. 59 
to 125° (48°°8 to 51°-6 Cent.) excites the tentacles 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 sea 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 piunged, and as in all cases waved about 
for a few minutes, in water at 180° (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 181°, 
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 ageregated ; 
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° (87°°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 180° (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. 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 
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 185° 
* Sachs states (‘Traité de Bo- were exposed for 1 m. in water to a 
tanique,’ 1874, p. 855) that the temperature of 47° to 48° Cent., or 
movements of the protoplasm in the 117° to 119° Fahr. 
hairs of a Cucurbita ceased after they 
