ALCOHOLISM AND BEHAVIOR OF WHITE RATS 211 



METHODS 



a. Source of material 



The rats used in this paper were raised from a series of three 

 brother-by-sister matings; two of these matings were made from 

 two htters of rats from The Wistar Institute Standard Stock. 

 The third line resulted from the combination of four lines from 

 independent sources, inchiding The Wistar Institute and Johns 

 Hopkins University; these were brought together in a series of 

 experiments on the same subject in which all the matings were 

 made between unrelated individuals, instead of between brothers 

 and sisters, as in the present series. The pedigrees of the rats 

 are given in figure 1; those given alcohol were marked 'A.' In 

 each strain one pair was given the alcohol treatment and one 

 pair, litter mates of the alcoholized rats, was raised as normal 

 controls. When the alcohol treatment was started, the plans 

 involved a very much larger number of rats than appears in 

 the results. The present report is based on the alcoholization 

 of six rats, although 112 rats were given the alcohol treatment. 

 The great reduction in the size of the experiment was due to 

 circumstances resulting from the war. In the third stram there 

 appears a second pair of rats (101/125) marked 'A.' These 

 were concerned in the first series of experiments and were given 

 a light dosage, increasing from thirty minutes a day at thirty 

 days up to ninety minutes a day at fifty days. Since these 

 rats are the common ancestors of both the test and the control 

 animals in this strain, it is clear that the control rats in this strain 

 are not strictly comparable with those in other strains ; but within 

 this strain the controls are strictly comparable with the alcohol- 

 ized rats. Moreover, the three strains may still be put together, 

 because: 1) the results (unpublished) of training the offspring 

 of the lightly alcoholized ancestors, that is, the generation to 

 which the pair 295/286 belongs, appear to indicate that the 

 treatment of the parents did not modify the behavior of the 

 offspring; 2) even if there should remain some effect of the first 

 alcoholization, this would work in the direction of reducing the 

 difference that has been found between the tests and controls; 



