86 PRINCIPLES OF BREEDING. 



tributes certain portions of the organization to the 

 offspring, and that each has a modifying influence upon 

 the other. Facts also show that the same parent does 

 not always contribute the same portions, but that the 

 order is reversed. Now, as no operation of nature is 

 by accident, but by virtue of laiv, there must be fixed 

 laws here, and there must also be, at times, certain in- 

 fluences at work to modify the action of these laws. 

 Where animals are of distinct species, or of distinct 

 breeds, transmission is usually found to be in accord- 

 ance with the rule above indicated, i. e. the male gives 

 mostly the outward form and locomotive system, and 

 the female chiefly the interior sj^stem, constitution, &c. 

 Where the parents are of the same breed, it appears 

 that the portions contributed by each are governed in 

 large measure by the condition of each in regard to age 

 and vigor, or by virtue of individual potency or superi- 

 ority of physical endowment. 



This potency or power of transmission seems to be 

 legitimately connected with high breeding, or the con- 

 centration of fixed qualities obtained by continued de- 

 scent for many generations from such only as possess 

 in the highest degree the qualities desired. On the 

 other hand it must be admitted that there are excep- 

 tional cases not easily accounted for upon any theory, 

 and it seems not improbable that in these the modifying 



