Page:Life Movements in Plants.djvu/121

Rh nued application, however, causes a second arrest, but this time in a state of relaxed expansion.

CuSO$4$ Solution.—This agent acts as a poison, causing a gradual diminution of amplitude of response, culminating in actual arrest at death. Certain poisons, again, exhibit another striking symptom at the moment of death, an account of which will be given in a separate paper.

With Mimosa, after each excitation the recovery becomes complete after a resting period of about 15 min. With this interval of rest the successive responses for a given stimulus are equal, and are at their maximum.

Experiment 30.—When the resting interval is diminished the recovery becomes incomplete, and there is a