12 



E. L. THORNDIKE. 



which ran up over a pulley in the front, across the box i inch 

 above the bars, over a pulley near the corner of the box, and 

 down to the floor, where it was fastened. Pulling on this string, 

 either by clawing at it where it was running vertically from the 

 last pulley to the floor, or by putting the paw out between the 

 bars which covered the top of the box, and clawing the string 

 downwards, would raise the bolt. If both bolts were raised and 

 cither bar was pushed up or down far enough to be out of the 

 way, the cat could escape. K, or ' Triple,' as it may be called, 

 is the box reproduced in Figure i. 



L was a box that also required three acts to open the door. 

 It was a combination of A (O at front), D (string), I (lever). 

 The lever or bar to be depressed was 2 inches to the right of 

 the door, which was in the front center. The string to be 

 clawed or bitten ran from front center to back center i inch 

 below the top of the box. 



Z was a box with back and sides entirely closed, with front 

 and top closed by bars and screening, with a small opening in 

 the left front corner. A box was held in front of this and 

 drawn away when the cats happened to lick themselves. Thus 

 escape and food followed always upon the impulse to lick them- 

 selves, and they soon would immediately start doing so as soon 

 as pushed into the box. The same box was used with the im- 

 pulse changed to that for scratching themselves. The size of 

 this box was 15 x lox 16. 



Experiments with Cats. 



In these various boxes were put cats from among the follow- 

 ing. I give approximately their ages while under experiment. 



