No. 645] ALCOHOL AND WHITE RATS 295 



eight days giving differences in the same direction is the 

 same as the probability of eight coins coming down all 

 heads; in the long run this will happen once in 256 

 tosses. The chances of seven out of eight, 1 to 32, of six 

 heads out of eight, 1 to 9. Carrying this comparison 

 further by considering all the generations together, the 

 chances of finding three cases favoring the tests out of 

 thirty-two are in the neighborhood of 1 to 860,000. From 

 all this it appears that the test rats are different, as a 

 group, from the controls. Apparently the only differ- 

 ence between the tests and controls that could explain 

 this result is the alcohol treatment given directly, or in 

 the ancestry of the test rats ; this leads to the conclusion 

 that the difference in behavior is due to the alcohol 

 treatment. 



Behavior in the Multiple Choice Apparatus 

 The difference in the behavior of the tests and controls 

 in the generation of the untreated offspring of treated 

 parents is further shown by the training on the multiple 

 choice apparatus. This is the only generation from which 

 sufficient data were gathered for the analysis of behavior 

 on this apparatus. 



Apparatus and Training— The apparatus used in this 

 training consisted of a linear series of nine compart- 

 ments, with front and back doors operated at a distance 

 by the observer (see Yerkes, '21, for history and uses 

 of this apparatus). Different sets of front doors were 

 opened for the successive trials and the rat was given 

 its reward of food by raising the back door when it en- 

 tered the ''correct" compartment. The ''correct" 

 compartment was the one at the extreme right or left 

 (according to the problem) of the series with open front 

 doors. In successive trials, therefore, the correct com- 

 partment was never the same one, and the solution of 

 the problem did not depend upon the repetition of a reg- 

 ular kinesthetic habit. The steps in the training were 

 these: at the age of 65 days the preliminary training 



