62 DROSERA ROTUNDIFOLIA. [Cuap. IV. 
always, become inflected; and the protoplasm within their 
cells undergoes aggregation, though the spheres thus formed 
are extremely small, with many of the cells partly filled 
with brownish muddy matter. In two instances, when leaves 
were immersed in water, at a lower temperature than 130° 
(54°°4 Cent.), which was then raised to 145° (62°°7 Cent.), 
they became during the earlier period of immersion inflected, 
but on being afterwards left in cold water were incapable of 
re-expansion. Exposure for a few minutes to a temperature 
of 145° sometimes causes some few of the more sensitive 
glands to be speckled with the porcelain-like appearance ; 
and on one occasion this occurred at a temperature of 140° 
(60° Cent.). On another occasion, when a leaf was placed in 
water at this temperature of only 140°, and left therein till 
the water cooled, every gland became like porcelain. Ex- 
posure for a few minutes to a temperature of 150° (65°°5 
Cent.) generally produces this effect, yet many glands retain 
a pinkish colour, and many present a speckled appearance. 
This high temperature never causes true inflection; on the 
contrary, the tentacles commonly become reflexed, though to 
a less degree than when immersed in boiling water; and this 
apparently is due to their passive power of elasticity. After 
exposure to a temperature of 150° Fahr., the protoplasm, if 
subsequently subjected to carbonate of ammonia, instead of 
undergoing aggregation, is converted into disintegrated or 
pulpy discoloured matter. In short, the leaves are generally 
killed by this degree of heat; but owing to differences of 
age or constitution, they vary somewhat in this respect. In 
one anomalous case, four out of the many glands on a leaf, 
which had been immersed in water raised to 156° (68°°8 
Cent.), escaped being rendered porcellanous ; * and the proto- 
plasm in the cells close beneath these glands underwent some 
slight, though imperfect, degree of aggregation. 
Finally, it is a remarkable fact that the leaves of Drosera 
rotundifolia, which flourishes on bleak upland moors through- 
* As the opacity and porcelain-like of coagulation is lower. The leaves 
appearance of the glands is probably 
due to the coagulation of the albumen, 
lmay add, on the authority of Dr. 
Burdon Sanderson, that albumen 
coagulates at about 155°, but, in 
presence of acids, the temperature 
of Drosera contain an acid, and per- 
haps a difference in the amount con- 
tained may account for the slight 
differences in the results above re- 
corded. 
