PHILOSOPHICAL TRANSACTIONS. 
I. On the Electromotive Properties of the Leaf of Dionceci in the Excited and 
Unexcited States. 
By J. Burdon-Sanderson, M.D., F.P.S., Professor of Physiology in 
University College , London. 
Received October 27,—Read December 15, 1881. 
In 1873 I communicated to the Society the results of experiments showing that in the 
leaf of Dionsea, 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 Poyal 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 
MDCCCLXXXI I. B 
