20 RESPONSE IN’ THE LIVING AND NON-LIVING 
deflection of 1 mm. at a distance of 1 metre. For a 
quick and accurate method of obtaining the records, I 
devised the following form of response recorder. The 
curves are obtained directly, by tracing the excursion of 
the galvanometer spot of light on a revolving drum 
(fig. 8). The drum, on which is wrapped the paper for 
receiving the record, is driven by clockwork. Different 
speeds of revolution can be given to it by adjustment of 

Fie. 7.—Recorp or Responses In Puant (LEAF-STALK OF CAULIFLOWER) 
BY MetHop or NEGATIVE VARIATION 
The first three records are for stimulus intensity 1; the next six are for in- 
tensity twice as strong; the successive responses exhibit fatigue. The 
vertical line to the left represents ‘1 volt. The record is to be read from 
right to left. 
the clock-governor, or by changing the size of the driving- 
wheel. The galvanometer spot is thrown down on 
the drum by the inclined mirror M. The galvanometer 
deflection takes place at right angles to the motion of the 
paper. A stylographic pen attached to a carrier rests on 
the writing surface. The carrier slides over a rod parallel 
to the drum. As has been said before, the galvano- 
meter deflection takes place parallel to the drum, and 
