336 



ROBERT M. YERKES 



times the worm came into contact with the strip of sandpaper 

 and the number of times it received the chemical (or elec- 

 trical) stimulus. 



The subject was permitted neither to retrace its course 

 thru the stem of the T to the entrance tube, nor to escape 

 by the arm containing the sandpaper. 



The instant the "head" of the worm entered the exit tube 

 the experimenter stopped the stop-watch .and recorded the 

 results of the trial. 



For convenience, as well as accuracy, in the recording of 



Figure 2. Ground plan of T, showing path followed by earthworm No. 2 in trial 

 10. (In this figure and the following one, fig. 3, a piece of blotting paper 

 soaked in salt solution took the place of the electrodes at E.) 



data an outline of the apparatus, similar to that of figure 2, 

 was cut in rubber and on the blank impressions produced with 

 this stamp the observer recorded (a) the number of the "trial," 

 (b) the hour, (c) the total time for the "trip," (d) the number 

 of contacts with the sandpaper, (e) the number of chemical (or 

 electrical) stimulations, and (f) the path followed. Supplemen- 

 tary notes concerning features of the behavior frequently were 

 appended. 



Experimentation with worm No. 2 was begun October 12, 

 191 1. On that day it was given ten trials in the apparatus. An 



