74 DROSERA ROTUNDIFOLIA. CHAP. IV. 



pinkish colour, 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 0> 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.f 



It may be worth adding 1hat immersion in cold 



* As the opacity and porcelain- differences in the results above 



like appearance of the glands is recorded. 



probably due to the coagulation t It appears that cold-blooded 

 of the albumen, I may add, on the animals are, as might have been 

 authority of Dr. Burdon Sander- expected, far more sensitive to an 

 son, that albumen coagulates at increase of temperature than is 

 about 155, but, in presence of Drosera. Thus, as I hear from Dr. 

 acids, the temperature of coagula- Burdon Sanderson, a frog begins 

 tion is lower. The leaves of Dro- to be distressed in water at a tern- 

 sera contain an acid, and perhaps perature of only 85 Fahr. At 95 

 a difference in the amount con- the muscles become rigid, and the 

 taincd may account for the slight animal dies in a stiffened couditiou 



