92 ZEBRAS, HORSES, AND HYBRIDS 



to know when to stop. Carried too far it undoubtedly 

 leads to degeneracy. In the ' Domesticated Animals 

 of Great Britain,' Lowe records the case of a gentleman 

 who inbred foxhounds to such an extent that ' the race 

 actually became monstrous and perished.' Hogs, if 

 too closely inbred, grow hair instead of bristles; their 

 legs become short and unable to support the body ; 

 and not only is their fertility diminished, but the 

 mothers cannot nourish the young. That infertility 

 is induced by inbreeding is further shown by some 

 experiments of Ritzema Bos with rats. From seven 

 rats of one family and an unrelated male he continued 

 inbreeding for a period of some six years, and bred 

 about thirty generations. The average of the numbers 

 in each litter fell from 7J in 1887 to 4.^ in 1891 and 

 2r in 1892. Further, the offspring of inbred parents 

 are usually weak. Sir Everett Millais estimated that 

 60 to 70 per cent, of inbred dogs attacked by distemper 

 were carried off. 



On the other hand, inbreeding often succeeds even 

 when carried to what the ordinary man would con- 

 sider excess. The ' Herd-book' contains the following 

 case in point. The bull Bolingbroke and the cow 

 Phoenix were more closely related to one another 

 than half-brother is to half-sister. They were mated, 

 and produced the bull Favourite. Favourite was then 

 coupled with his dam, and produced the cow Young 

 Phoenix ; he was then coupled with his daughter 

 Young Phoenix, and the world-famed Comet was the 

 result. Professor Ewart tells us that if there was 

 little crossing in the production of Comet, there was 

 still less in that of Clarissa, the mother. of the cele- 

 brated Restless. An instance of the faith in close 

 inbreeding which exists in the minds of breeders 

 occurred in a letter which the Field published in 1898, 

 in which the writer stated he had heard 'Mr. Joseph 

 Osborne, the ablest authority living on English 



