OTHER PIGEON HYBRIDS AND BREEDING OF CERTAIN SPECIES. 173 



the "strongest germs" an undue proportion of "pairs" of eggs produce males and 

 that from the opposite period there arise undue numbers of pairs of eggs that 

 produce females. To lump these altogether and to count the number of males 

 arising from first and females from second eggs is plainly to cover up or 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 consider- 

 able total predominance of males or of females, and the statistical method lumps 

 all without thought or care of the cancellations 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 it has been demonstrated by the author that not only is the method pre- 

 viously employed gravely at fault, but that the material used, in nearly all of those 

 cases where the worker has thought it worth while to mention what form was 

 studied, has been wholly unsuitable for leading to a decision; that is to say, the 

 "pigeons" used were in most cases one or another of the 150 "mongrels" collectively 

 known as domestic pigeons. One of the clearest points of our present knowledge of 

 the relation of sex to egg of clutch is that the normal relations of these are lost 

 immediately tcpon hybridization — i.e., in passing from the -pure state of the species. 

 The countless degradations and crossings suffered by the various "domesticated 

 breeds" of pigeons since their existence as a pure wild species is, therefore, a 

 sufficient index of the unsuitability of this material in a study of this subject. 



Among all of the published statements to date, only in that of Cuenot does one 

 find even a suggestion which points in the direction of recent findings and toward a 

 reconciliation or understanding of the discordant data hitherto reported. Cuenot'" 

 suggested that sex-production from the pigeons' clutches may vary in the different 

 races and subraces of pigeons. This point, if applied to some domestic races, as 

 compared with some pure wild species, would certainly be wholly true ; possibly it is 

 true also among the races and subraces of which he speaks. 



It now seems certain that in many wild species of pigeons the rule is for the first 

 egg of the clutch to produce a male and for the second to produce a female. It 

 also seems probable that this order is normally reversed in some other wild species." 

 It is probable, moreover, that included in some species which normally produce a 

 predominance of males from first and of females from second eggs there are excep- 

 tional individuals which quite regularly present the sexes in the reverse or in an 

 irregular order. But these subsidiary points, together with the frequency of the 

 reversals of order of the sexes in the "very first clutch" of the season (possibly also 

 in the very last clutch under certain conditions) have not been adequately dealt 

 with by the author, nor are they satisfactorily decided by his data; they must 

 therefore await further and future analysis. These particular topics have been 

 under investigation by the editor during the past 4 years. A large amount of data, 

 obtained from several different lines of study, is still being accumulated and will 

 probably not be long delayed in publication. 



' "Statistical results, giving the averages of taany cases, give the average of chances. We want to know what 

 happens under normal or prescribed conditions, with chance eliminated to the utmost. Statistics lead away from the 

 careful study of the individual cases, on the assumption that such cases can not be understood except in the mass, 

 where individuals are lost. It is evident that the result in any case depends upon all of the particulars, and the more 

 thoroughly these are understood the better the result can be understood." (W 8.) 



•1 Bui. Sci. France et Belg., vol. 32 (5th ser., vol. 1), 1899. 



" Possibly the purity of these species should be questioned. 



