34 Animal Intelligence 
K was a box arranged so that three separate acts were rb- 
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 1 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 1. 
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 tobe 
clawed or bitten ran from front center to back center 1 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. 
