154: PRINCIPLES OF STOCK-BREEDING. 



sented, it appears that in-and-in breeding has been 

 quite generally practised by those who have been the 

 most successful in improving the different breeds, and 

 it is probable, to say the least, that they have all made 

 use of it with a common purpose. 



( If those having the greatest reputation in the art 

 had resorted to the practice of in-and-in breeding, on 

 account of the direct influence it was in itself sup- 

 posed to exert in the improvement of animals, they 

 would undoubtedly have made use of it to a greater 

 extent than they have done.) 



From a careful examination of the pedigrees we 

 have quoted, or any others that may be found in the 

 herd-books and breeding-registers, representing the 

 practice of breeders of acknowledged reputation, it 

 will be found that in-and-in breeding has only been 

 resorted to in the case of some favorite animal or ani- 

 mals that were superior in certain respects to the 

 average members of the herd or family which they 

 represent, and the object has evidently been to se- 

 cure, in their offspring, a predominance of their most 

 highly-valued characters. 



From the complex relations of the multitude of 

 hereditary characters in animals, which have been 

 derived, as we have seen, from all of their ancestors, 

 the modifying influences of food and habit cannot 

 affect all animals in precisely the same degree or 

 manner, and they cannot, therefore, be expected to 

 produce the same modifications in the characters of 

 a large number of animals at the same time. The 

 breeder who makes an intelligent use of these modi- 

 fying agencies, in the improvement of his stock, will 



