LAW OF CORRELATION. 89 



jority of these cases, assumes more the form of hair 

 than of wool." 1 



The tusks, which attain a great size in the boar, 

 are not fully developed in swine that are castrated. 8 



What are called the secondary sexual characters of 

 the male are not developed in animals that are cas- 

 trated ; and, among birds, it has been observed that 

 females incapable of breeding, from age or the effects 

 of disease, sometimes assume the plumage and voice 

 of the male. 3 



The cock of the Sebright bantams should be hen- 

 tailed and without sickle-feathers, thus presenting a 

 close resemblance to the female. This character, so 

 highly prized by exhibitors, has, however, its disad- 

 vantages. 



Mr. Hewitt remarks, in regard to these breeds: 

 " The combined experience of many other admirers 

 of the Sebright bantams is concurrent with my own, 

 viz., that even a very trifling disposition to sickle- 

 feather in the tail brings with it proportionably in- 

 creased productiveness ; and that, on the other hand, 

 absolute perfection of hen-tailed character in the male 

 bird as generally entails sterility." * 



The tail is entirely wanting in Rumpless fowls, 

 and it is said that they " are sadly prone to lay unfer- 

 tilized eggs." 6 



The law of correlation, in its relations to structure 



9 Journal of the Royal Agricultural Society, vol. xv., p. 285. 



3 " Animals and Plants under Domestication," vol. ii., p. 68. 



4 Tegetmeier on " Poultry," p. 245. 

 8 Ibid., p. 232. 



