Chap. XVII. EVIL FROM INTERBREEDING. 101 



celebrated Improved Essex breed, divided his stock into three 

 separate families, by which means he maintained the breed for 

 more than twenty years, "by judicious selection from the three 

 distinct families." 21 Lord Western was the first importer of a 

 Neapolitan boar and sow. "From this pair he bred in-and-in, 

 until the breed was in danger of becoming extinct, a sure result 

 (as Mr. Sidney remarks) of in-and-in breeding." Lord Western 

 then crossed his Neapolitan pigs with the old Essex, and made the 

 first great step towards the Improved Essex breed. Here is a more 

 interesting case. Mr. J.Wright, well known as a breeder, crossed" 

 the same boar with the daughter, granddaughter, and great-grand- 

 daughter, and so on for seven generations. The result was, that 

 'in many instances 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 

 last 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 external form or merit of the young ; but with 

 many of them the general constitution and mental powers, and 

 especially the reproductive functions, were seriously affected. 



Nathusius gives 23 an analogous and even more striking case: he 

 imported from England a pregnant sow of the large Yorkshire 

 breed, and bred the product closely in-and-in for three generations : 

 the result was unfavourable, as the young were weak in constitution, 

 with impaired fertility. One of the latest sows, which he esteemed 

 a good animal, produced, when paired with her own uncle (who was 

 known to be productive with sows of other breeds), a litter of six, 

 and a second time a litter of only five weak young pigs. He then 

 paired this sow with a boar of a small black breed, which lie had 

 likewise imported from England ; this boar, when matched with 

 sows of his own breed, produced from seven to nine young. Now, 

 the sow of the large breed, which was so unproductive when paired 

 with her own uncle, yielded to the small black boar, in the first 

 litter twenty-one, and in the second litter eighteen young pigs ; so 

 that in one year she produced thirty-nine fine young animals ! 



As in the case of several other animals already mentioned, even 



21 Sidney's edit, of ' Youatt on the Col. Le Couteur, who has done so 

 Pig,' 1860, p. 30; p. 33, quotation much for the agriculture of Jersey, 

 from Mr. Druce ; p. 29, on Lord writes to me that from possessing a 

 Western's case. fine breed of pigs he bred them very 



22 'Journal of Royal Agricult. Soc. closely, twice pairing brothers and 

 of England,' 1846, vol. vii. p. 205. sisters, but nearly all the young had 



23 ' Ueber Rindvieh,' &c, s. 78. tits and died suddenly. 



