DISTRIBUTION OF EFFORT IN LEARNING IN WHITE RAT 3 



left hand corner of one side of the box was a door 15 cm. by 

 18 cm. The box as well as the door was covered with wire 

 netting of 1.3 cm. mesh. A wooden latch attached to the frame 

 of the box fitted in a notch in the door. Inside the door there 

 was a light spiral spring which opened the door when the latch 

 was released and it also held the latch more firmly in the notch. 

 The hood that covered the latch box had a base 50 cm. square 

 and 43 cm. high. It was hinged to the top of a table to prevent 

 it shifting out of position. Opposite the hinged side, and about 

 25 cm. from the door of the latch box, was the entrance of the 

 hood. An entrance box of wire netting admitted the rat to the 

 hood. The latch box remained always in the same position on 

 the table under the hood. 



FIG. I 



LATCH BOX. 



