DELAYED REACTION 25 



SO that when it was raised the three faces cleared the floor prac- 

 tically the same distance. The faces and the front half of the 

 top of R are covered with glass ; the rest is of wood. The docfrs 

 leading into the light boxes are 4" x 3". Those leading out of 

 the light boxes, called exit doors here, are 3" x 2^". The switches 

 at S' are for the lights which are of the same intensity and 

 wiring arrangement as those in the two preceding boxes. The 

 switches at S turn the current into any or all cf the paths from 

 the release box to the light boxes. This current is obtained 

 from a dry cell and is passed through the primary coil of a Porter 

 inductorium. The strength of the current passing into the prob- 



FiGURE 3. Box C 



lem box was regulated so that the animals never became fright- 

 ened by severe shocks. The current was never strong enough 

 to cause the animals to squeak and only rarely did they attempt 

 to jump over the strips. The brass strips from which the shocks 

 were obtained (only one group, marked B, is shown in this 

 figure), were very thin and lay flat on the floor of the box. 

 Before being tacked down, they were given an acid bath which 

 destroyed their lustre but left their conductivity practically 

 unaft'ected for my pui-]Do.se. 



Fig. 3 should give a clear presentation of the essentials of 

 this box as well as of the others used in the course of this 

 research. 



