Ko.645] ALCOHOL AND WHITE BATS 301 



Size of Litters. — A general tendency for the litters of 

 the test rats to be smaller than the controls persists in 

 the summaries of all generations. The difference be- 

 tween the size of the litters from the original treated rats 

 and the litters from the controls is equal to 10.5 per cent, 

 of the size of the control litters. The treated offspring of 

 the treated rats produced litters that were 10.3 per cent, 

 smaller than the litters of their controls. It appears, 

 therefore, that the treatment of the parents' of the litters 

 as well as the grandparents does not intensify the reduc- 

 tion in litter size found when only one generation was 

 treated. The untreated offspring from treated rats gave 

 litters that were 11.2 per cent, smaller than their controls, 

 and the untreated offspring from untreated parents and 

 treated grandparents gave litters that were 13.1 per cent, 

 smaller than the controls (see Fig. 4). These differences 

 in individual generations are based on too few cases to 

 be significant when compared with their probable errors, 

 but when the numbers are increased by taking all the gen- 

 erations together, the probable error is reduced so that 

 the difference attains statistical significance (3.6 times 

 its probable error). Litter size, then, gives a result not 

 unlike that given by the behavior data: the tests are 

 inferior in each generation, with no apparent relation to 

 the proximity of the alcohol or the number of generations 

 of treatment. 



Number of Litters. — G-iven equal time, the treated pairs 

 produced 0.72 litter per pair while the controls produced 

 2.07 litters per pair. This is a reduction o^ 64.8 + 3.3 

 per cent, in the number of litters, and as it is 19.2 times 

 its probable error, it is significant beyond all question. 

 The test litters were slower in appearing than the con- 

 trols. The treated rats from treated parents also gave 

 fewer litters than their controls, but instead of a greater 

 reduction than in the previous generation this second 

 treated generation produced relatively more litters. The 

 reduction was 35.4 + 6.9 per cent, of the controls. Com- 

 ing to the rats not directly treated, the untreated rats 



