The contractile effect of light is seen not only in the retardation of growth, but also by the char­ac­ter­is­tic modi­fi­ca­tion of pulsation of Desmodium in the diminution of diastolic limit of expansion.

The antagonistic reactions of light and warmth are found not only in growth but also in the rhythmic activity of Desmodium gyrans. In the pulsation of Desmodium the contractile effect of light induces a rapid diminution of the diastolic limit of expansion, while the expansive reaction of warmth brings about a marked reduction of the systolic limit in successive pulsations.

XXI.—A COMPARISON OF RESPONSES IN GROWING AND NON-GROWING ORGANS

By

Sir J. C. Bose,

Assisted by

Guruprasanna Das.

I have in the preceding series of Papers demonstrated the effects of various forms of stimuli on growth. I have also given accounts of numerous reactions which are extraordinarily similar, in growing and non-growing organs. In fact certain char­ac­ter­is­tic reactions observed in motile pulvinus of Mimosa and other ‘sensitive’ plants led to the discovery of the corresponding phenomena in growing organs. For fully realising the essential similarity of responses given by all plant-organs, growing and non-growing, I shall give here a short review of the striking character of the parallelism.