Page:Researches on Irritability of Plants.djvu/104

Rh irresponsive, and only after a period of rest can it exhibit excitation. The same phenomena are observed in the case of the contractile organ of Mimosa. Here also, after

erection (expansion) under continuous stimulation, the leaf is irresponsive and only renews its excitability after a definite period of rest.

As regards this particular reaction in Mimosa, we are

in a position to trace out the various phases through which contraction under single stimulus is reversed to expansion under fatigue induced by continuous stimulation. It has