198 CHARLES R. STOCKARD AND GEORGE N. PAPANICOLAOU 



two types of spermatozoa in certain male animals. And there 

 is evidence to show, as cited in our previous paper, that the 

 fertilizing power of the spermatozoa may be modified in such a 

 way as to render them much less capable of success. If this is 

 the case, we may be justified in assuming that one class of 

 sperm may often, even under normal conditions, be at a disad- 

 vantage as compared with the other. It is even more prob- 

 able that under modified conditions the two morphologically 

 different classes of spermatozoa will not be affected to equal 

 degrees. 



In conclusion, then, it seems highly probable that the peculiar 

 sex-ratios shown by the several groups of treated animals re- 

 corded in table 6 are in part due to differential sex mortalities 

 during early prenatal stages, on account of the close correlation 

 between the sex-ratios and the average litter sizes. This differ- 

 ence in early prenatal mortality between the sexes does not, 

 however, completely satisfy the case. The sex-tendency of the 

 animals considered and the possibility in the case of delicate 

 treatment of affecting the two types of spermatozoa in different 

 ways or degrees are certainly factors to be recognized in the 

 production of the results obtained. 



Pearl found that for fowls treated with alcohol the relative 

 proportions of the sexes produced were not significantly different 

 from normal control series. Our results for the sex-ratio of the 

 total alcoholic series agree with Pearl's findings. The sex-ratio, 

 of the 594 alcoholic animals considered in the present paper is 

 105.6, which, in view of the numbers involved, is not signifi- 

 cantly different from the control series. Yet studying separately 

 the several groups shown in table 6, w^e find strikingly wide dif- 

 ferences in the sex-ratios and the arrangement of these differ- 

 ences is decidedly consistent. From the standpoint of the 

 above discussion it seems to us legitimate to consider the six 

 groups individually, or at least as three classes, since there is a 

 probability that different processes or conditions are affecting 

 the results in the different cases. Several recent experiments 

 on the modification of the sex-ratio would tend to strengthen such 

 a probability. 



