No. 595] 



SEX CONTROL IN PIGEONS 



CHART IV 



Stored Energy of Eggs (1914) of Streptopelia risoria (558) as Deter- 



781 Jl 12/12 I 1.535 



782 J2 12/14 ! 1.690 



1 This egg was not only the first laid during season, but first during lile 

 of this bird. 



2 The percentage differences are based upon a value of 100 per cent, for 

 the smaller egg of the pair. 



numbers of pairs of eggs that produce females. To 

 lump these all together and to count the number of males 

 arising from first, and females from second eggs is plainly 

 to cover up or to lose the significance of the intervening 

 pairs of eggs which bear the significant data. Again, 

 many matings, because of exceptional strength or of 

 weakness, will yield a considerable total predominance of 

 males or of females, and the statistical method lumps all 

 these and others without thought or care of the cancella- 

 tions and unsatisfied cancels involved; all of which as 

 easily contributes to a smoothing of the results, as it does 

 to a smothering of them. 



But Whitman has also shown that not only is the 

 method previously employed at fault, but that, much more 

 important still, the material used -in probably all of 

 those cases in which no correspondence of sex to the 



