Page:Insectivorous Plants, Darwin, 1899.djvu/76

 CHAPTER IV. THE EFFECTS OF HEAT ON THE LEAVES.

I my observations on Drosera rotundifolia, the leaves seemed to be more quickly inflected over animal substances 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 eflScient. Another interesting point presented itself, namely, at what degree life was extinguished; 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 especially in the failure of the protoplasm to become aggregated, when the leaves after being heated are immersed in a solution of carbonate of ammonia.