208 PRINCIPLES OF STOCK-BREEDING. 



may be the case, from the fact that in each successive 

 cross the relative potency of the pure-bred male would 

 be diminished, as the females to which he is bred are 

 improved in their characters. 



On the other hand, it might seem probable that 

 the improvement of the female would increase the 

 tendency to a predominance of the desired characters, 

 and thus intensify the influence of the male in the 

 further improvement of the family. But cross-bred 

 animals do not, as a rule, transmit to their offspring, 

 as dominant characters, the peculiarities that they have 

 derived from a superior breed, even when they appear 

 to predominate in their organization; .. . 



When both parents are cross-bred animals even 

 in cases in which they both resemble the superior race 

 from which they have derived their most obvious 

 characteristics the prevailing tendency in their pow- 

 ers of transmission is shown in the frequent recur- 

 rence of remote ancestral characters in their offspring. 



In attempts to establish a new breed by crossing, 

 this tendency to atavic transmission can only be over- 

 come by a persistent and long-continued system of 

 selection. " Changes, in fact, by crossing, are not to 

 be effected in a short space of time ; you must look 

 forward to several years of constant exertion, before 

 you can hope, in this manner, to alter your stock." 



Mr. Hogg says : " By the attempt which has been 

 made to renovate the Scottish flocks by the Cheviot 

 blood, we see the unexpected length of time necessary 

 for completing and confirming the change. 



" 'No class of animals which I am acquainted with 



1 Blacklock on "Sheep," p. 115. 



