74 DROSEKA EOTUNDIFOLIA. Chap. IV. 



piukish colour, and many present a speckled appear- 

 ance. This liigli 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 coliverted 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 tJie 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°.t 



It may be worth adding that immersion in cold 



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



like appearance of the glands is recorded. 



j)rnl)iil)ly tluc to the coai^ulation f It appears that cold-blooded 



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



authority of Dr. liurdon 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- Burden Sanderson, a frog begins 



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



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



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



tuined may account for the slight animal dies in a stiffened condition. 



