INTELLIGENCE OF EARTHWORMS 335 



ment afforded it. Between September, 191 1, and September, 

 1 91 2, it doubled its size. 



Each day, in preparation for the experiments with No. 2, 

 the blotting paper upon which the glass T rested was soaked 

 with tap water, as were also the paper linings of the entrance 

 and exit tubes. The apparatus was then set with the stem of 

 the T directed toward and perpendicular to a north window 

 which was the sole source of illumination during experimenta- 

 tion. The strip of sandpaper now was properly placed beneath 

 one arm of the T at 1 centimeter from the adjacent wall of 

 the stem, and just beyond it, on the plate glass base, instead 

 of on the blotting paper, a thin piece of glass supporting a strip 

 of blotting paper soaked in salt solution was adjusted. 4 



When the apparatus was in readiness the experimenter re- 

 moved the worm from its jar by inverting the latter over a 

 dish and emptying the entire contents. Then with a fine camel's 

 hair brush the worm was removed to a small dish of water, to 

 wash off any adhering particles of earth. Thence it was care- 

 fully, but quickly, transferred to the lower half of the entrance 

 tube and immediately covered with the upper half to protect 

 it from the light. 



A "trial" or "test" was given as follows: Having placed 

 the entrance tube containing the worm at the base of the stem 

 of the T, with the anterior end of the worm directed toward 

 the T, the experimenter removed the cover of the tube, thus 

 permitting the light from the window to drive the negatively 

 phototactic worm into the T. If the light did not within a few 

 seconds cause the subject to move forward, it was lightly stroked 

 along the dorsum of the terminal segments with a moist camel's 

 hair brush. 



No. 2 usually started quickly, and especially in the later 

 experiments, without being "touched." 



The experimenter noted, by referring to a watch, the moment 

 of uncovering the tube, and registered the beginning of the trip 

 thru the T by starting a stop-watch the instant the head 

 of the worm entered the stem of the T. He then observed 

 minutely the behavior of the worm in the apparatus, recording 

 as accurately as might be the path followed, the number of 



4 In the later experiments with worm No. 2 the strip of rubber and the electrodes 

 took the place of the apparatus for chemical stimulation. 



