180 CHARLES R. STOCKARD AND GEORGE N. PAPANICOLAOU 



treated-female line during later generations can probably be 

 explained in part by the higher mortality of the offspring in the 

 first generation, thus bringing about a greater elimination of the 

 weaker individuals. In other words, these animals from only 

 female ancestors treated have withstood a somewhat more 

 severe selection during the first generation than have the off- 

 spring from only treated male ancestors. 



As a final possibility it must be recognized that the superior 

 records of the late generations descended from treated female 

 ancestors as compared with the records of similar generations 

 descended from treated males, may be due to a smaller influence 

 of the alcohol treatment on the ova, or female germ cells, than 

 on the spermatozoa. 



The sixth column from treated male and female ancestors 

 shows, in comparison with the two preceding columns, the highest 

 'early prenatal mortality' based on the many small-size litters. 

 There is also the lowest average litter weight. The late prenatal 

 mortality, total mortality, and mating failures, while higher than 

 for the treated-female line, are lower than in the treated-male 

 line. The complete absence of matings between directly treated 

 animals as seen in the third column of this table makes com- 

 parisons and explanations of the results in this sixth column 

 very difficult. 



The last three columns of the table show the combined re- 

 sults from all generations. The column for both male and 

 female ancestors treated shows the highest early prenatal mor- 

 tality, the male treated line the highest late prenatal mortality, 

 and the female treated line the highest postnatal mortality. 



In general it may be stated after reviewing this and the fore- 

 going table that the treatment of males produces in their de- 

 scendants a high early mortality, especially early prenatal. The 

 treatment of females produces in their descendants a high later 

 mortality, especially late prenatal and postnatal. The treatment 

 of male and female ancestors produces in their descendants 

 the highest early prenatal mortality, but the lowest late pre- 

 natal and postnatal mortality. 



