PROF. J. C. BOSE ON ELECTRIC RESPONSE IN PLANTS. 275 
Electric Response in Ordinary Plants under Mechanical 
Stimulus. By Prof. Jacapis Cuunper Boss, M.A., D.Sc. 
(Communicated by the President.) 
[Read 20th March, 1902.] 
ConTENTs. 
Introduction.—Conditions for obtaining Electric Response,— Negative 
variation.—Experimental arrangements.—Response Recorder.—Means of 
graduating the intensity of Stimulus—Block method.—Plant-response, a 
physiological response.—Responses to single stimuli.— Uniform responses.— 
Staircase effect—Fatigue.—Increased_ effect with increasing stimulus.— 
Superposition of stimulii—Diphasie Variation.—Abnormal Response.— 
Influence of temperature on Plant-response.—Determination of Death- 
point.— Effects of Anzsthetics and Poisons.—Conclusion. 
INTRODUCTION. 
Tue effect of stimulus on living substance is usually detected 
by two different methods. In the case of motile organs, stimulus 
causes a change of form. Mechanical response may thus be 
obtained in a contractile tissue such as muscle. But in others— 
nerve for example—stimulus causes no visible change; the 
excitation of the tissue may, however, be detected by certain 
electromotive changes. The advantage of the electric mode of 
detecting response is its universal applicability. In cases where 
mechanical response is available, as in muscle, it is found that 
simultaneous mechanical and electrical records are practically 
identical. 
The intensity of electrical response is found to depend on the 
physiological activity of the tissue. When this activity is 
diminished by anesthetics, the intensity of electrical Tesponse 
is also correspondingly diminished. When the tissue is killed, 
the electrical response disappears altogether. 
Electric response has been found by Burdon Sanderson, Munck, 
and others to occur in sensitive plants. We have seen that in 
animal tissues this mode of response was not confined to con- 
tractile tissues, but present in others which exhibit no mechanical 
movement. It would therefore be interesting to find out 
whether the responsive electric variation was confined merely to 
organs of plants which exhibit such remarkable mechanical 
movements, or whether such effects are not also exhibited by every 
plant and by all its different organs. 
