IN-BREEDING 225 



lands. These cattle have been kept pure in various 

 private parks of Great Britain and have for many hundred 

 years been subjected to conditions which compelled 

 extensive in-breeding. These cattle have not perished, 

 they are not weak in constitution and are not decreasing 

 in size. This example is often quoted as an argument 

 in favor of in-breeding. Darwin's critical analysis of 

 this classic example leaves us still in doubt as to its value 

 as a demonstration of the beneficial results which may be 

 expected to follow long-continued in-breeding. 



1 " The half-wild cattle," says Darwin, " which have 

 been kept in British parks probably for 400 or 500 years, 

 or even for a longer period, have been advanced by Culley 

 and others as a case of long-continued inter-breeding within 

 the limits of the same herd without any consequent injury. 

 With respect to the cattle at Chillingham, the late Lord 

 Tankerville owned that they were bad breeders. The 

 agent, Mr. Hardy, estimates (in a letter to me dated 

 May, 1861) that in the herd of about 50 the average num- 

 ber annually slaughtered, killed by fighting and dying, 

 is about 10, or one in five. As the herd is kept up to 

 nearly the same average number, the annual rate of in- 

 crease must be likewise about one in five. The bulls, 

 I may add, engage in furious battles, of which battles 

 the present Lord Tankerville has given me a graphic 

 description, so that there will always be rigorous selec- 

 tion of the most vigorous males. I procured in 1855 

 from Mr. D. Gardner, agent to the Duke of Hamilton, 

 the following account of the wild cattle kept in the Duke's 

 park in Lanarkshire, which is about 200 acres in extent. 

 The number of cattle varies from 65 to 80 ; and the num- 

 ber annually killed (I presume by all causes) is from 8 



1 Darwin, "Animals and Plants under Domestication," p. 97. 

 Q 



