GRADE BREEDING. 



WE have seen already that cross breeding 

 was properly divisible into two classes the 

 interbreeding of two distinct breeds or varieties 

 where both were improved breeds, and the in- 

 terbreeding of one such breed with an unim- 

 proved or native stock. We have now to discuss 

 the latter method. 



This breeding of one animal of an improved 

 breed with another of an unimproved or native 

 stock is usually spoken of as grading or grading 

 up. By grading is meant a leveling, step by 

 step by gradations, to use a word of exactly 

 similar derivation. This grading is just the 

 same process as the word signifies when we 

 apply it to mechanical work, as grading a 

 street. It is, however, here used in the sense 

 of leveling up. - Hence the frequent use of the 

 additional preposition "up." The aim is not 

 merely to level, as is most commonly done in 

 mechanical work by getting a mean between 

 the highest and lowest points though this is 

 not infrequently all that is really attained but 

 the aim is to raise the average to the maximum 

 and to make the grade level with the highest 

 point. In short, to make a "fill" rather than a 



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