INTELLIGENCE OF EARTHWORMS 345 



In view of this positive result of the training, it was deemed 

 worth while to proceed with the next step in the investigation, — 

 namely, amputation of the anterior segments, with the "brain," 

 in order that the relation of the habit to the "brain" might be 

 studied. 



At 5 p. m. on April 30 the prostomium, the first four seg- 

 ments and about half of the fifth were amputated with a sharp 

 pair of scissors. The worm was in splendid physical condition 

 at the time. It reacted markedly for a few seconds but not 

 violently to the mutilation. Immediately after the operation 

 it was placed between layers of moist filter paper in a jar. Thus 

 it was left over night. 



When uncovered and exposed to the light at 10 a. m., May 1, 

 it immediately began to crawl forward. It seemed very sensitive 

 to photic and tactual stimuli, and it moved freely both forward 

 and backward. The wound, which had closed, appeared to be 

 in excellent condition. After the examination, the filter paper 

 was removed, the jar washed and the worm replaced between 

 layers of fresh paper. 



So wholly satisfactory was the condition of the subject on 

 May 2, 40 hours after the operation, that it seemed desirable to 

 resume experimentation. 



With the apparatus arranged precisely as in the previous 

 series of trials, (April 30) the worm was permitted to enter the 

 T. It moved forward, more slowly and continuously than 

 before the operation, into the middle of the stem. Thence it 

 proceeded by a path which is reproduced in figure 4. Having 

 reached the "common" wall of the arms, it turned to the left 

 and five times pushed forward to the sandpaper, each time 

 withdrawing upon contact. As it searched with the cut end, for 

 a way of escape, the "tail" became active and moved about 

 as if "feeling" for a path. Shortly a turn toward the right was 

 made and, with repeated attempts to crawl up the glass wall, 

 the worm approached the exit tube. The instant the "head" 

 end came in contact with the moist lining of the tube the worm 

 pushed forward as in "recognition" of the retreat. 



The trial which has been described was given at 9:16 a. m., 

 and at 9 130 a second trial resulted in a direct trip thru the T. 

 The note-book record reads: "Entered quickly and directly. 

 With 'head' end raised 3-4 millimeters from the floor and in 



