34 Animal Intelligence 



K was a box arranged so that three separate acts were re- 

 quired to open the door, which was held by two bolts at the 

 top and two bars outside. One of the bolts was connected 

 with a platform in the back center of the box so that depress- 

 ing the platform raised the bolt. The other was raised by a 

 string 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. Pull- 

 ing on this string, either by clawing at it where it was run- 

 ning 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 downward, would raise the bolt. 

 If both bolts were raised and either 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 (0 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-hand 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 themselves, and they soon would im- 

 mediately start doing so as soon as pushed into the box. 

 The same box was used with the impulse changed to that 

 for scratching themselves. The size of this box was 

 15 x 10 x 16. 



