174 CHARLES R. STOCKARD AND GEORGE N. PAPANICOLAOU 



the high percentage of small litters and low percentage of large 

 litters and consequently the very low average litter of 2.31. 

 This is likely due to the male partner in the combination, as the 

 preceding columns would suggest. The average litter weight, 

 however, is high, so that the individual members of the litter 

 are as heavy as the normal; this, again, may be due to the male 

 influence as expressed in the high early prenatal mortality. 



The mortality records, though markedly inferior to the nor- 

 mal, show an advantage over the two previous columns. There 

 is probably a high 'early prenatal mortality' as indicated by the 

 low average litter, but the 4ate prenatal mortality' is lower 

 than in any of the foregoing columns except that of the treated 

 fathers, where again the .litter was very small and the prob- 

 able 'early prenatal mortality' high. This close association be- 

 tween the small litters and the low late prenatal mortality makes 

 it seem all the more probable that the litter size is associated 

 with an ' early prenatal mortality' that occurs so near the begin- 

 ning of development that it cannot be directly observed. On 

 the other hand, this result could be interpreted as due to a 

 lowered fertility. If this were brought about through an elimi- 

 nation of the w^eaker germ cells we might except also the asso- 

 ciated low late prenatal and postnatal mortality, and w^ould 

 have a condition in exact accord with Pearl's interpretation of 

 the results on fowls. We should be glad to accept such an ex- 

 planation, but for the considerable amount of evidence in our 

 records which points towards a high 'early prenatal mortality' 

 rather more than infertility as the underlying cause of the small 

 litters and low late mortality. It must also be remembered 

 that the infertility among the fowls was found in the females as 

 well as the males, while here it would be confined to the males 

 only. 



The slight advantages which appear in favor of the records 

 from both parents alcoholic as compared with records from alco- 

 holic mothers or fathers are due largely to the distance from the 

 treatment of the generations concerned. In the majority of 

 cases the generations are more remote in the both-parent column 

 than in either the father or mother column, and on the basis of 



