62 DROSERA ROTUNDIPOLIA. [Chap. IV. 



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 thfe more sensitive glands to be speckled with the porce- 

 lain-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 tempyerature of only 

 140, and left therein till the water cooled, every gland be- 

 came like porcelain. Exposure for a few minutes to a tem- 

 perature 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 tem- 

 perature of 150 Fahr., the protoplasm, if subsequently sub- 

 jected to carbonate of ammonia, instead of undergoing 

 aggregation, is converted into disintegrated or pulpy dis- 

 coloured matter. In short, the leaves are generally killed 

 by this degree of heat; but owing to diflferences 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 

 rolundifolia, which flourishes on bleak upland moora 

 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.* 



Ah the opnolty and porce- ture of ronpnlntlon Is lower. 



Inln-liko apponraiioe of the The leaves of Drosera contain an 



Klands Is prol)nl)ly due to the co- acid, and perhaps n dilToreuce In 



a^rnlatlon of the alhutneD, I may the amount contained may ac- 



ndd. on the authority of Dr. count for the slight dirferencea In 



Ilnrdon Sanderson, that albumen the results above recorded, 



coatrnlates at nlM>i't 1S5*, but. In It appears the cold-blooded 



presence of acids, the tempera- animals are. as might have l>een 



