ALCOHOLISM AND BEHAVIOR OF WHITE RATS 215 



sisting of five concentric alleys with doorways and blind alleys 

 so arranged that the correct path from the outside to the center 

 required a rat to turn alternately to the right and then to the 

 left at the successive doorways. Two large mirrors were sus- 

 pended from the ceiling above the maze in such a way as to 

 direct the image of the maze into a set of lenses that focused it, 

 greatly reduced, upon a sheet of paper. With the maze bril- 

 liantly illuminated and the light cut off from the paper by a 

 dark box, the observer could plainly see on the paper the image 

 of the rat as it went through the maze and could make a perma- 

 nent record of the rat's course by following it with a pencil. 

 A diagram of the maze as it appeared reflected on the paper was 

 printed upon the sheets used to record the course of every trial 

 of each rat (fig. 7). Frequentl}^ it was necessary to use several 

 sheets to record a very long trial, in order to make it possible 

 afterward to understand the course taken by the rat. The 

 time required for each trial was recorded on these sheets. 



When the rats were forty-nine days old their training was 

 started. They were given seven days of preliminary training, 

 which consisted of feeding them in the inner circle of the maze 

 shut off from the alley. This was followed by the training proper 

 (subsequently to be called 'training'), consisting of three suc- 

 cessive trials a day for eight days. The rat was allowed to taste 

 the food between trials, but was removed from the center as soon 

 as it had taken a bite; after the third trial the rat was allowed to 

 eat for five minutes. The food consisted of white bread and 

 milk. At the end of the eight days of training, the rat was 

 started upon the preliminary training on a multiple-choice 

 apparatus. Thirty-one days were spent on the multiple-choice 

 apparatus. At the end of this time the rat was returned to the 

 maze to test its retention of the maze habit. The retention 

 trials were continued, three a day, for four days. The results 

 of the training on the multiple-choice apparatus will appear in 

 a later paper. 



