332 THE CROSSING, AC, OF CATTLE, ET AL. 



the conditions of life be decidedly unfavorable to the 

 characters of either parent breed." 



It is for this object, namely, the formation of new 

 varieties, that crossing is resorted to. It is also re- 

 sorted to, as, seen above, to procure fine animals for 

 immediate consumption. The other reason that it is 

 adopted, is to ward off the evils which have accrued, 

 from interbreeding. This motive seldom obtains with 

 respect to Cattle and Sheep, unless there has been very 

 long-continued and very close-interbreeding. With 

 animals, like the Pigeon, the Fowl, and the Pig, as has 

 been already shown, breeders of the high fancy breeds 

 are constantly compelled to have recourse to crossing. 

 Yet, even with Cattle and Sheep, the breeder, in push- 

 ing the peculiarity, of a breed, to an extreme point, 

 needs must interbreed the individuals ; this leads to its 

 natural, evil results; and crossing is then required. 

 The criterion, generally, with breeders, of the good 

 resulting from a cross, is, whether the offspring has 

 improved or deteriorated, in the quality precious to the 

 breeder. It may have improved most wonderfully, iji 

 a physiological sense, and have regained every char- 

 acter of its species, in a comparatively high degree of 

 development; yet, if it has abated the least, in the spe- 

 cial excellence required for the breeder's purpose, it is 

 esteemed shamefully deteriorated; although all immu- 

 nity from danger, for tens of generations, from the 

 closest interbreeding, may have succeeded previous 

 loss of (nigh) all fertility. 



When a breed is suffering from the results of close- 

 interbreeding, there is no necessity to cross with a 



