IN-AXD-IN BREEDIXG. 95 



serious degree ; but it is not proved that this degener- 

 acy, although very common and even usual, is yet a 

 necessary consequence. That ill effects follow in a 

 majority of cases is not to be doubted, but this is easily 

 and suJSciently accounted for upon other grounds. In 

 a state of nature animals of near afiSnities interbreed 

 without injurious results, and it is found by experience 

 that where domesticated animals are of a pure race, or 

 of a distinct, well defined and pure breed, the coupling 

 of those of near afiiuities is not so often followed by 

 injurious effects as when they are crosses, or of mixed 

 or mongrel origin, like the great majority of the cattle 

 in the country at large. In the latter case breeding 

 in-and-in is usually found to result in decided and rapid 

 deterioration. We should consider also that few ani- 

 mals in a state of domestication are wholly free from 

 hereditary defects and diseases, and that these are pro- 

 pagated all the more readily and surely when possessed 

 by both parents, and that those nearly related are more 

 likely than others, to possess similar qualities and ten- 

 dencies. 



If such is to be regarded as the true explanation, it 

 follows that the same method would be also efficacious 

 in perpetuating and confirming good qualities. Such 

 is the fact ; and it is well known that nearly all who 

 have achieved eminence as breeders, have availed them- 



