B- 



D 



Figure 2. Ground Plan of Multiple Choice Apparatus Used for Pigs. Scale 



A, reaction mechanisms, nine similar boxes or stalls; V, stall number 4; 0, en- 

 trance door of box; P, exit door of box; T, food trough of box; G, observer's stand 

 and H, writing table; D, runway between trough, T, and stand, G; S, S, yards; 

 B, reaction space; R, E, alleys or runways connecting D with S; I, observer's en- 

 trance door to apparatus; J, observer's entrance door to reaction space B; L, M, 

 slide doors between* yards and reaction space; K, N, slide doors between yards 

 and alleys. 



The weighted cord systems for operating the entrance and exit doors (twenty 

 in all) are not shown in this figure. They may be seen in figure 1, A, B, and C. 



