224 



HAROLD E. BURTT 



alley and the food-dish F. To facilitate its re-entrance into E, 

 a light wooden door D was hinged to a frame sliding along the 

 wall of the side alley S. Pulling a string caused this door to 

 swing across the alley and then slide along in a transverse posi- 

 tion toward the entrance box. This cut off the animal's retreat 

 and, if necessary, pushed it into the entrance box. Another 

 string pulled this device back to its original position. 



Figure 1. Ground plan of multiple-choice apparatus for rats. Scale 1:10 

 E, entrance-box; R, reaction-chamber; C, reaction-mechanisms; A, back alley; 

 S : side alley; D, sliding door; F, food-dish. The doors (except D) moved ver- 

 tically and were operated by weighted cords through screw-eyes not shown in the 

 figure. 



The interior dimensions of the nine compartments were: 

 width 3 in., length 8 in., depth 4 in. Each front door was 24 in. 

 from the door of the entrance box E. The alleys were 4 in. wide, 

 the entrance box 6x6 in. and the entire apparatus 4 in. deep. 



