XII.—THE EFFECT OF CHEMICAL AGENTS ON GROWTH
By
Sir J. C, Bose,
Assisted by
GURUPRASANNA DAS.
Chemical agents are found to exert characteristic actions on growth. The method of investigation sketched here opens out an extended field of investigation. The oll'ect of a chemical substance, I find, to be modified by (I) the strength of the solution, (2) the duration of application, and (3) the condition of the tissue. A poisonous substance in minute doses is often found to exert a stimulating action. Too long continued action of a stimulant, on the other hand, exerts a depressing effect. The influence of the tonic condition is shown by the fact that while a given dilution of a poisonous substance kills a weak Specimen, the same poisonous solution, applied to a vigorous specimen, actually stimulates and enhances the rate of the growth. I give below descriptions of a few typical re- actions.
The reagent, when in a liquid form, is locally applied on the growing organ. The records, taken before and after the application, exhibit the stimulatory or depressing character of the reagent. A different method of application of the reagent is employed for plants with extended
