THE PROBLEM OF INBREEDING 107 



another of the scheme of^ Lehndorff . This plan 1 

 took account, as a measure of inbreeding, only of 

 the number of generations intervening between 

 that generation in which relatives were bred 

 together, and that generation in which their first 

 common ancestor was found. Thus Lehndorff 

 says : 2 



"I am of opinion, that a horse should only be 

 termed in-bred, when in sum total less than four 

 degrees lay between its parents and their common 

 ancestor ; in other words, when the children or 

 grandchildren of a stallion or a mare are mated, I 

 call their produce in-bred; but this term does not 

 apply to the produce of great-grandchildren of the 

 common ancestor. We must not forget that in 

 the pedigrees of horses the word brother or sister 

 often means half-brother or half-sister, and that 

 here the definition borrowed from the human 

 family connection is not applicable. 



"As breeding within moderate relationship I 

 reckon the mating of stallion and mare that are 

 removed from their common ancestor four, five, or 

 six degrees. It is indifferent whether they are on 

 both sides equidistant from, or one of them nearer 

 to the male or female progenitor than the other." 



Von Oettingen used a measure exactly the same 

 in principle as this of Lehndorff's. The system of 



1 Cf. Lehndorff, G. "Horse-breeding Recollections," Phila- 

 delphia, 1887. 



1 Loc. cit., p. 49. 



