66 DROSERA ROTUNDIFOLIA. Chap IV. 



CHAPTEE ly. 



The Effects of Heat on the Leaves. 



Nature of the experiments — Effects of boiling water — Warm water 

 causes rapid inflection — Water at a higher temperature does not 

 cause immediate inflection, but does not kill the leaves, as shown 

 by their subsequent re-expansion and by the aggregation of the 

 protoplasm — A still higher temperature kills the leaves and 

 coagulates the albuminous contents of the glands. 



In my observations on Drosera rotwidifolia, the leaves 

 seemed to be more quickly inflected over animal sub- 

 stances, and to remain inflected for a longer period 

 during very warm than during cold weather. I 

 wished, therefore, to ascertain whether heat alone 

 would induce inflection, and what temperature was 

 the most efficient. Another interesting point pre- 

 sented itself, namely,- at what degree life was extin- 

 guished ; for Drosera offers unusual facilities in this 

 respect, not in the loss of the power of inflection, but 

 in that of subsequent re-expansion, and more espe- 

 cially in the failure of the protoplasm to become 

 aggregated, when the leaves after being heated are 

 immersed in a solution of carbonate of ammonia.* 



* When my experiments on the eludes that the protoplasm with- 

 eflfects of heat were made, I was in their cells always coagulates, 

 not aware that the subject had if in a damp condition, at a tem- 

 been carefully investigated by perature of between 50° and 60° 

 several observers. For instance, Cent., or 122° to 140° Fahr. Max 

 Sachs is convinced (' Traite do Schultze and Kiihue (as quoted 

 I3otani(iue,' 1874, pp. 772, 854) by Dr. Bastian in 'Coutemp. 

 that the most ditfercnt kinds of Review,' 1874, p. 528) " found 

 plants all perish if kt'pt for 10 m. that the protoplasm of plant- 

 in water at 45° to 40° Cent., or cells, with which they experi- 

 113° to 115° Fahr. ; and he con- mented, was always killed and 



