58 INHERITANCE, FERTILITY, AND SEX IN PIGEONS. 



egg-production further "weakens" the germs; and late season brings, in some way, 

 a still further "weakness." It is from this sort of "reduced fertility" — a fertility 

 founded upon weakness — ^that females have been obtained which are more adequate, 

 more complete (in respect to fertility) than their brothers. Such weakness of 

 developmental energy may produce, according to these data, a relatively perfect 

 individual of the "weaker sex," but not a perfect individual of the sex which must 

 go "further in development than the female." ^ 



It is largely because of the obvious bearing which these data have upon Whit- 

 man's conception of the relation which the sexes bear to fertility, that advantage 

 was taken of this large family to make a thorough study of the fertility of its 

 members. Some of the same sort of thing may be found in many of the families 

 bred by Professor Whitman himself, and he was plainly convinced that the weak 

 fertility of a germ tends to be reproduced as weak fertilitj', and as weakness of 

 other sorts, into the germs of the next generation. But an early examination of 

 his data, together with some indications and references to this pair (which he had 

 mated in 1910; see table 26), convinced the editor that the parents of this particular 

 family should be left mated, the greatest possible number of offspring secured, and 

 the fertility of these adequately studied. This chapter is, then, the result of such 

 an effort. 



Three means are used in the presentation of the results: (1) a very general 

 textual statement; (2) a condensed table, followed by tlie more important individual 

 tables which give a better and more detailed idea of the situation; (3) a vevy short 

 and inclusive history (in smaller type) of the essential facts which a critical survey 

 of the evidence would require. It will be noted that an attempt has been made to 

 test the fertility of these young with each other and with another species (St. alba) 

 with which T. oricntalis is normally quite fertile. 



An examination of the condensed tabulation (table 28) shows that all of the 

 7 males were deficient as males; 3 had opportunity to mate (after sexual maturity, 

 of course) and failed; 3 others mated, copulated with egg-laying females, normally 

 fully fertile with this species, and proved in all of many tests absolutely infertile. 

 One male (421) which arose late in the season, but from a clutch of eggs which 

 threw 2 viales, was very weakly fertile. When a little less than a year old (with 

 St. alba) this male proved practically infertile; 4 eggs were produced; 2 showed no 

 trace of development, the other 2 gave rise to 2-day and 4-day embryos. During 

 a second year half of the eggs tested with another alba were hatched, though half 

 of the young died very early (see table 31). In his third year, Avith still another 

 St. alba, this male is responsible for 20 absolutely infertile eggs and no fertile ones. 



On the other hand, 2 females, the first and third, proved to be highly fertile, 

 the first (500), with two different St. alba males, the third (433) with an inbred 

 "mutant" T. orientalis ' (108). The second female (481) of the season has not 

 yet been properly tested as to fertility, largely because of her low and peculiar 

 fecundity and her abnormal eggs and egg-laying instincts. It turns out that the 

 4 of her eggs properly tested were laid within 3 months of the death by tuberculosis 

 of her male {St. alba) consort. The infertility of these 4 eggs is, therefore, of little 

 or uncertain significance (see table 29). This female is most remarkable for having 



« See Chapters V-VII, Volume 1. 



' This pair gave rise to the series of end-of-the-season "mutants" described and figured in the preceding chapter. 



