106 PRINCIPLES OF BREEDING. 



of crossing breeds possessing distinctive characteris- 

 tics : 



" Crossing is generally understood to refer to the 

 alliance of animals of diflferent breeds, such as between 

 a thorough-bred and a half-bred among horses or a 

 South Down and Leicester among sheep. Now the 

 advantages or disadvantages of this system depend 

 entirely on the object we have in view, whether merely 

 to beget an animal for the butcher, or for the purpose 

 of perpetuating the species. If the latter is the object, 

 then crossing should be adopted gradually and with 

 care, and by no means between distant or antagonistic 

 qualities, as for example a thorough-bred and a cart- 

 horse. The result of the latter connection is generally 

 an ill-assorted and unfavorable animal, too heavy per- 

 haps for one purpose, and too light for another. If we 

 wish to instil more activity into the cart-horse breed, it 

 is better to do so by means of some half-bred animal, 

 whilst the latter can be improved by means of the three- 

 parts-bred horse and this again by the thorough-bred. 

 There is a remarkable tendency, in breeding, for both 

 good qualities and bad to disappear for one or two gen- 

 erations, and to reappear in the second and third ; thus 

 an animal often resembles the grand dam more than the 

 dam. This peculiarity is itself an objection to the prac- 

 tice of crossing, as it tends to prevent uniformity and 

 to encourage contrarieties ; and thus we find in many 

 flocks and herds that the hopes of the breeders have 

 been entirely baffled and a race of mongrels estab- 

 lished. 



