24 



WALTER S. HUNTER 



through screw-eyes on the top of the box, to the experimenter 

 at E. 



A i6 c.p. light was suspended about four feet from the floor 

 over the center of the apparatus. Its intensity was diminished 

 approximately by two-thirds by wrapping the bulb in cloth. 

 The three light boxes were covered in order to prevent light 

 from entering them from above. Part of the entrance box 

 leading to the release, R, was covered by the switch-board, S, 

 and the remainder by paste board. This prevented the animals 

 from watching the experimenter. 



Figure 2. Ground plan of Box C. D, exit door. 



Box B was, in principle, like Box A. It was used in testing 

 the dogs. Its dimensions differed from those of A. Instead 

 of being 90 degrees, the extreme lateral angles w^ere 75 degrees. 

 The angles on each side of the middle light box were about 

 145 degrees as opposed to 127 for Box A. Box B was only 

 2' high, and the length of its entrance box was 1' 4". The re- 

 lease box was covered with wire, and each face was 1' x 10". 

 The distances from the release boxes to the light boxes were 

 each i^'. 



Fig. 2 is a ground plan of Box C. This box was used for 

 rats. In addition to the data there given, the following points 

 should be noted: The release box, R, was fastened by hinges 



