280 PROF. J. C. BOSE ON ELECTRIC RESPONSE IN 
panying figure is a photographic record of another set of response- 
curves (fig. 3), which should be read from right to left. 
The first three responses are for a given intensity of stimulus, 
and the next six in response to stimulus nearly twice as strong. 
It will be noticed that fatigue is exhibited in these responses. 
Other experiments will be described which show conclusively 
that the response was not due to any accidental circumstance, 
but was a direct result of stimulation. But I shall first discuss 
the experimental arrangements and the method of obtaining these 
graphic records. 
Fig. 3. 
Photographic record of negative variation in plants. 
Fig. 4. 
Response Recorder. 
Experimental Arrangements. 
The galvanometer used is a sensitive dead-beat D’Arsonval. 
A current of 10—° ampere gives a deflection of 1 mm. at 4 
distance of 1 metre. 
Response -Recorder.—In these response-curves the ordinate 
