FERTILITY 103 



tion of both male and female individuals. The breeder 

 emphasizes the existence of those general qualities which 

 give to the male a distinctly masculine appearance and 

 to the female a clearly recognizable character of femininity. 

 The bull possessing a markedly masculine aspect is held 

 to be a " good breeder." Whether it is meant by this 

 that such a bull is prepotent in fixing his own charac- 

 teristics upon his offspring or, what is more probable, 

 that a bull of this character is more than ordinarily effi- 

 cient in the development of sperm-cells, it is still true 

 that the masculine type may be regarded as in some 

 degree at least correlated with fertility. Supernumerary 

 mammae have been found in many cases associated with 

 exceptional fertility. In describing the dam of triplet 

 calves, Pearl 1 remarks : " It is of interest to note that 

 this cow has two very small posterior mammae. It is 

 of course impossible to say whether this occurrence of 

 supernumerary mammae is directly connected with the 

 high degree of fecundity exhibited by this cow, but this 

 may fairly be regarded as probably the case because of 

 the fact that these two things are known to be associated 

 in other forms." The sheep breeding experiments at 

 Beinn Bhreagh 2 by Alexander Graham Bell have suggested 

 a possible correlation between extra nipples and unusual 

 fecundity. Stature and fertility have been found by 

 Pearson 3 to be somewhat closely correlated among women. 

 The taller women are on the average more fertile. If this 

 is generally true, the stature of women is likely to increase 

 at least until it has reached a point which satisfies the 

 correlation existing. Among swine-breeders it is generally 



1 Loc. tit. 



2 Bell, Science, N. S., vol. 36, pp. 378-384. 



3 Pearson, "Grammar of Science," pp. 441-445. 



