As regards the action of light, the pulsation continued
for a,time, even on the cessation of light. This per-
sistence of autonomom activity increases with the intensity
and duration of incident stimulus, that is to say with
the amount Of incident energy. In the present ease
a duration of five minutes’ exposure gave rise to a
single pulsation, after which the movement of the leallet
came to a stop. The next application lasted for ten
minutes and this gave rise to four pulsations, two during
application, and two after cessation of light. The next
application ,was for forty-live minutes, and the pulsation
persisted for nearly an hour after the cessation of light.
The experiments on sub-tonic specimens show clearly that.
the enerey supplied by the environment heci-mes as it
were latent in the plant, increasing its potentiality for
work.
The renewal of autonomous activity in a sub—tonic tissue. by the. action of external stimulus, will he found in every way parallel to the l'uiewal of growth in a sub-tonic organ.
REVIVAL OF GROWTH UNDER. STIMULUS.
Renew/(.1 of growth MIN/(’1' s/inm/us: [import/mm], .91.--” I find that application of electric stimuhm paupws gmle in specimens whore, on account of extreme sub-tonicity growth has come to a state of standstill. The resumption of grOWth in grass haulms under the Stimulus “f gravity is a phenomenon probably connected with the almvp, '11“, causes which bring about cessation of growth in a mature organ are unknown; that there is a potentiality of growth even in a fully grown grass haultn is evidenced by the fact of its renewed growth under fresh stimulation. That this is not an exceptional phenomenon appears from the record which I obtained with a fully grown style of
