118 BEBEDING IN-AHU-IN. 



constantly breeding witli his own daughters, and, if he lives 

 long enough, with his grand - daughters ; and his male 

 successors must commence breeding with sisters and continue 

 it with their descendants. All these animals are, de facto, 

 paired together by that Being who created their instincts and 

 gave them their habits. Is there any visible proof that their 

 races have become physically degenerate on this account? 

 Are not the lion and the elephant as large, healthy and 

 powerful as they were ages ago? 



No one pretends to the contrary. But we are told — 

 and this was Sebright's argument — that a natural provision 

 was also made to prevent animals from degenerating from the 

 effects of in-and-in breeding. " A severe winter, or a scarcity 

 of food, by destroying the weak and the unhealthy, has all 

 the good effects of the most skillful selection." And he might 

 have added, that the strong male kills the weak male, the herd 

 trample down the sick and the feeble, and gore to death the 

 wounded. Such causes, imdoubtedly, combine to extirpate 

 what may be termed accidental degeneracy. But these facts 

 do not go far enough to sustain the position of those who 

 believe that in-and-in breeding necessarily results in degen- 

 eracy. If it did, instead of a few, the whole or nearly the 

 whole flock or herd or family, in such cases as 'I have 

 m^entioned, would perish ; and whole races would long since 

 have become extinct. 



The moment we step from the domain of nature to the 

 domain of man, the scene changes. "We have treated our 

 domesticated animals as we have treated ourselves. By 

 artificial surroundings — by changing the natural habits m 

 regard to nutrition, exercise, etc. — by cruelty or kindness — 

 by breeding the diseased with the healthy — we have brought 

 malformation, infirmity, disease and premature death among 

 all of them ; and we have continued the causes imtil we have 

 made the effects a part of the physical systems, and thoroughly 

 hereditary among them. Therefore no longer, like the free 

 normal denizens of the forest and the air, can they follow 

 their natural instincts with impunity ; and the inter-breeding 

 of the infirm and diseased, and especially of infirm and 

 diseased relatives, must, as in the case of man, be prevented. 

 But all the facts I have ever seen or ascertamed fi-om 

 entirely reliable sources, go to show that the inter-breeding of 

 relatives, and even near ones, is innocuous when both parents 

 are free from aU defects and infirmities which tend to impair 

 ■ the normal physical organization. It is difiicult to improve 



