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crossed the same boar with • the daughter, grand- 

 daughter, and great-granddaughter, and so on, for 

 seven generations. The result was, that, in many in- 

 stances, the offspring failed to breed ; in others, they 

 produced few that lived; and, of the latter, many 

 were idiotic, without sense even to suck, and when 

 attempting to move, could not walk straight. Now, 

 it deserves especial notice, that the two best sows 

 produced by this long course of interbreeding, were 

 sent to other boars, and they bore several litters of 

 healthy pigs. The best sow, in external appearance, 

 produced during the whole seven generations, was one 

 in the last stage of descent ; but the litter consisted of 

 this one sow. She would not breed to her sire; yet 

 bred, at the first trial, to a stranger in blood, so that, 

 in Mr. Wright's case, long-continued and extremely 

 close-interbreeding did not affect the general form or 

 merit of the young; but, with many of these, the gen- 

 eral constitution, and mental powers, and especially 

 the reproductive functions, were seriously affected." 



With respect to this last remark of his, it may be 

 asked : How is it possible, in his eyes, for close-inter- 

 breeding to affect, unfavorably, the general form of 

 the young, when the very degeneration in form, 

 which is occasioned by interbreeding, is what he, and 

 other breeders of Pigs, esteem an improvement ? In- 

 terbreeding intensifies any evil in parts. So, when a 

 well-bred Pig has its legs, tusks, &c, further reduced 

 by such a process, Darwin looks upon such an effept, 

 as an improvement which but enhances the value of 

 the animal. The same simple remark he makes, when 

 speaking of Pigeons. As before noticed, he, with 

 charming simplicity, notes that the evil effects pro- 

 duced upon the form, is far more noticeable in the case 

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