I. On the electromotive properties of the leaf of dionæa in the excited and unexcited states

Abstract

In 1873 I communicated to the Society the results of experiments showing that in the leaf of Dionæa, as in the excitable organs of animals, the change of form which is the visible effect of mechanical or electrical excitation, is preceded by an electrical change of a nature similar to that which occurs, under corresponding conditions, in animal muscle. In a second paper, which was read on the 14th December, 1876, I submitted to the Society, in conjunction with Mr. Page, an account of a number of experiments, made, for the most part in the Laboratory of the Royal Gardens, Kew, with the aid of Lippmann’s electrometer, for the purpose of elucidating the relation between the electrical phenomena and the physiological process which they accompany. In that paper we confined ourselves to the mere relation of our observations, recognising their incompleteness, but hoping that the work of future seasons might yield better fruits. Although each year since 1876 some additions have been made to our knowledge, it has not seemed desirable to publish anything, until the present occasion. If the accumulated products of so many years appear insignificant, I must ask that it may be remembered that the investigation is one of great difficulty, and that the time during each summer which is available for experiment is very short. As almost all the experiments on which the conclusions of the present paper are founded have been of such a nature as to require the co-operation of two persons, it is obvious that the work could not have been accomplished without the aid of a practised observer. This aid I have received from Mr. Page, to whose technical skill and ingenuity in overcoming difficulties, whatever success may have been attained in the experimental part of the enquiry, is largely due.