IN-AND-IN BREEDING. 155 



rarely find more than one or two animals presenting 

 variations that approximate closely to the ideal stand- 

 ard of excellence he has adopted ; and, moreover, it 

 must be admitted that the same desired form of vari- 

 ation will be more likely to be obtained in those ani- 

 mals that have the closest resemblance in their hered- 

 itary tendencies and constitution. The truth of this 

 proposition is amply proved by experience, as we find 

 that the desirable variations that have laid the foun- 

 dation for the improvement of breeds, have, as a rule, 

 occurred in a few favored animals, belonging to the 

 same family, and closely related in blood. 



Distinct breeds of animals have originated, as we 

 have seen, through the influence of the conditions to 

 which they were subjected in particular localities, in 

 connection with a continued selection of those that in 

 their form and qualities resemble each other, while 

 those presenting diverging characters were rejected. 



In the improved breeds we have ingrafted upon 

 the original type the highly-artificial characters that 

 render the animal valuable for a special purpose, and 

 these, from their very nature, are more difficult to 

 retain than the less divergent characters of the origi- 

 nal breed. 



These artificial characters can only be secured, in 

 their greatest perfection, by persistent effort in the 

 systematic accumulation of slight variations in the 

 desired direction, and they can only be made the 

 dominant characters of a family or breed by breeding 

 exclusively from those animals in which they are the 

 most conspicuous. 



If, as may reasonably be expected, these characters 



