294 



ALDA GRACE BARBER 



from a dealer, January, 1913. They were approximately 6 

 weeks old at the time. Rats No. 19, No. 21 (males) and No. 20, 

 No. 22, No. 23, (females), reared in this laboratory, were about 

 2 months old at the time the experiment was begun upon them 

 (October, 1913.) No. 19 was dropped after the first preliminary 

 trials upon methods of learning, because the method in^which 

 it had been trained was discontinued. The older rats were 

 more deliberate in their movements than the younger. 



l*~ 



B' 



D' 



A 



K 



3?> 



E* 



E 



lit . 19 . 19 



H 



H 



a ra 



F 



r 



wj 



h q.X. 



Figure 1. Ground plan of apparatus, a, the stimulus board; b, the main 

 apparatus box; c, outer triangle; d, inner triangle; e, section 

 (approximately 2 ins. wide). 



APPARATUS AND GENERAL METHOD 



A. Apparatus. Apparatus Box — The apparatus in the present 

 study consisted of an eight-sided box surrounded by a stimulus 

 board. (See Figs. I & II.) All was made of light wood. The floor 

 of the box was divided into isosceles triangles, lettered A, B, C,.etc, 

 in order to facilitate the noting of the positions of the rat. The 

 sides of the box were divided into 32 sections all of which were 



