Page:Researches on Irritability of Plants.djvu/125

102 temperature had reached 60° C. there was an abrupt inversion, and the spasmodic contraction tool»: place at a very rapid rate. The successive dots in the rip-portion of the curve are at intervals of .2 of a. degree. The point of inversion, as we shall see, indicates the death-point, and the curve giving the death-record we shall call the. It should be remembered that the particular

electric response characteristic of living condition of the tissue is found to disappear after the tissue had been subjected to the temperature of 60° C.

If the sudden contraction that takes place at 60° C. should prove to be the death-spasm, then this should be the last response given by the plants. If we raise the temperature of the plant short of the dearth-point, say to 45° C., we get a continuous responsive expansion; when cooled the leaf recovers, to a greater or less extent, its