In -and- in - Breedin g 145 



tant relationship should be included. It is held 

 by some that breeding together animals which 

 have a more distant degree of relationship than 

 that known in the human family as aunt and 

 nephew or uncle and niece, should not be recog- 

 nized as coming within the meaning of this term. 

 On the other hand, others are emphatic in in- 

 cluding more remote relationship. 



In-and-in-breeding has played a most important 

 part in the formation of breeds and also in the 

 improvement of breeds that were well established. 

 As variation and selection enable the breeder to 

 produce individuals of superior merit, he will 

 naturally try to perpetuate this superiority arid 

 to reap the advantages of it through successive 

 generations in his herd or flock. This has been 

 made possible through in -and -in -breeding. Al- 

 most without exception marked improvement is 

 first noted in one or two animals. If the progeny 

 of these animals are bred to each other or to one 

 of their parents, the young resulting from this 

 mating will contain a much larger percentage of 

 the " blood " of the animal in which the improve- 

 ment was noted than could be obtained in any 

 other way. Consequently the chances that the 

 improvement will be transmitted are consider- 

 ably enhanced. 



In other words, in -and -in -breeding enables the 

 breeder to accumulate or " pile up " the blood of 



