PARENTAL ALCOHOLISM AND THE PROGENY 263 



The only plausible way to account for the origin of this difference 

 is to assume that the female-producing spermatozoa were more modified 

 by the treatment than the male-producing spermatozoa. Whether 

 such an increased modification is due to the presence of a greater mass 

 of chromatin to be injured in the one case than in the other or to a 

 difference in response on the part of the two heteromorphic sex chromo- 

 somes it is impossible to state. The difference, however, is a fact! 



A part of the pertinent data on this point in our fowls has 

 been presented in table 5. The remainder is exhibited in tables 

 7 and 8. Table 7 gives the sex of the progeny of treated par- 

 ents, by individual matings. The results by grouped matings 

 according to treatment are shown in table 5. 



Table 8 gives the sex ratio statistics for the series of matings 

 of normal Black Hamburg cf cf X Barred Plymouth Rock 9 9 

 made in 1913. All the parents in this series were untreated nor- 

 mal individuals. Again the data are arranged by individual 

 matings in order that an appreciation of the amount of varia- 

 tion in the sex ratio may be obtained. 



It is obvious from these tables that the male sex ratio varies 

 to a considerable degree, especially in the treated series. It is 

 doubtful, however, whether the matings in the treated series are 

 really significantly more variable in this respect, having regard 

 to probable errors. Giving each mating equal weight, that is 

 not weighting with fertility, we get the following constants: 



Treated c? X normal 9 9 : Unweighted mean cf sex ratio = 48.4 ±5.3% 

 Treated cf X normal 9 9 : Unweighted standard deviation = 26.3 ±3.8% 

 Treated d' X treated 9 9 : Unweighted mean cf sex ratio = 47.0=^7.1% 

 Treated cf X treated 9 9 : Unweighted standard deviation = 27.7='=5.0% 

 Normal cT d' X normal 9 9 : Unweighted mean d sex ratio = o3.2±2.4% 

 Normal cf cf X normal 9 9 : Unweighted standard deviation = 16.0 ±L7% 



Turning to the weighted means and their probable errors 

 given in tables 7 and 8 we derive the following set of differences 

 with their probable errors: 



Weighted mean cf sex ratio differences 



(Normal cfo" X normal 9 9) - (treated d X normal 9 9) = 1.1±3.6% 

 (Normal cfcf X normal 9 9) —.(treated cf X treated 9 9) = 4.5±4.7% 

 (Treated dd X normal 9 9) - (treated cf X treated 9 9) = 3.4±5.0% 



