6 'Journal of Comparative Neurology and Psychology. 



even after Z had opened the door, she stayed behind long enough 

 to pull the knot before following her out. Frequently X started 

 for the door when Z or Y began to pull the knot. She looked back 

 and forth from the knot to the door until the door opened then she 

 dashed out ahead of the other cat. She seemed to understand 

 that pulling the knot opened the door. At other times she quietly 

 looked on while Y opened the door, and then followed him out. 

 As she made but little effort to get out when in the box alone I 

 tried to arouse her to greater activity by spreading a wet towel over 

 the bottom of the box, but this expedient failed to produce the 

 desired result. 



Experiment J. Opening Door by Turning Button and Pulling Loop. 



Method.— A door of wire netting extended the full length of one 

 side of a wooden box (Box II) 72 cm. long, 47 cm. wide, and 48 

 cm. deep. In one end of this box, 5 cm. above the floor, a small 

 door (15 x 17 cm.) was made. This door was constructed of wire 

 netting so that food placed on the outside of the box could easily 

 be seen. The door was opened from the inside by turning a 

 wooden button and pulling a loop which was concealed by the 

 button. The button was 8 cm. to the right and a little above the 

 door. 



Results. — Z was in the box alone: 



Nov. 1 30' Nov. 5 3c/ 



Nov. 2 30' Nov. 6 30' 



Nov. 3 30' Nov. 7 30/ 



She turned the button several times during the first tw^o days, 

 but she did not pull the loop. During the last four days she did 

 not touch the button. Nov. 7, after Z had been in the box alone 

 for thirty minutes without touching the button, X was put in with 

 her. They got out four times in less than fifteen minutes. The 

 first two times X turned the button and Z pulled the loop, but the 

 last two times Z both turned the button and pulled the loop. Nov. 

 8, Z, while alone in the box, did not even touch the button, but 

 on Nov. 9 she succeeded in getting out in fifteen minutes. After 

 being put back she did not get out again in thirty minutes. How- 

 ever, after X was put in with her they succeeded in getting out 

 in twenty-five minutes. X turned the button and Z pulled the 

 loop. Nov. 10, Y was in the box alone for thirty minutes and in 



