74 DROSERA ROTUNDIFOMIA. Crap. IV, 
pinkish colcur, and many present a speckled appear. 
ance. This high temperature never causes true inflec- 
tion ; 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 tem- 
perature of 150° Fahr., the protoplasm, if subsequently 
subjected to carbonate of ammonia, instead of under- 
going 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 protoplasm 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 throughout Great Britain, and exists (Hooker) 
within the Arctic Circle, should be able to withstand 
for even a short time immersion in water heated to a 
temperature of 145°. 
It may be worth adding (that immersion in cold 
* As the opacity and porcelain- 
like appearance of the glands is 
probably due to the coagulation 
of the albumen, I may add, on the 
authority of Dr. Burdon Sander- 
son, that albumen coagulates at 
about 155°, but, in presence of 
acids, the temperature of coagula- 
tion is lower. The leaves of Dro- 
sera contain an acid, and perhaps 
a difference in the amount con- 
tained may account for the slight 
differences in the results above 
recorded. 
t It appears that cold-blooded 
animals are, as might have been 
expected, far more sensitive to an 
increase of temperature than is 
Drosera. Thus, as I hear from Dr. 
Burdon Sanderson, a frog begins 
to be distressed in water at a tem- 
perature of only 85° Fahr. At 95° 
the muscles become rigid, and the 
animal dies in a stiffencd condition 
