Page:Researches on Irritability of Plants.djvu/128

Rh found that there is induced an electric-spasm at the onset of death. When the temperature is rising, a given point of the plant-tissue exhibits increasing galvanometric positivity, till at the critical temperature there is a sudden electric inversion into galvanometric negativity. The

electric-curve of death is of the same type as the thermo-mechanical curve. With specimens of Musa and Amaranth the death-point was found to be 59.5° C.

As the death-spasm is a form of physiological response we should expect the curve of death to undergo modification under physiological variation. One such modification would lie in the translocation of the point of inversion, or the displacement of the death-point. Thus age has some influence, the death-point of very young specimens being lower than that of mature ones. I shall demonstrate