2 BREEDING 



student of heredity would profit much by a know- 

 ledge of the methods employed and the results ob- 

 tained by the other. It is a question which of the 

 two would gain most : the man of science by the 

 knowledge of the facts relating both to the successes 

 and the failures of the breeder ; or the breeder by 

 an acquaintance with the principles elucidated, and 

 the precision of the records kept and the methods 

 employed by the man of science. It is desirable 

 that the student of heredity should, for the sake of 

 his science, become interested in breeding. It is 

 desirable that the breeder should, for the sake of his 

 art, become interested in heredity. And, in general, 

 it is desirable that each should recognise that he has 

 much to learn from the other ; for though, as we 

 have seen, the objects of their work are different, 

 the problem which they are both investigating is the 

 same. 



My object in writing this book is to place within 

 reach of the practical breeder some of the things 

 found out by the scientific student of heredity, which 

 are likely to be of service to him. 



The methods of the breeder are two. They are, 

 as a matter of fact, nearly always used in conjunc- 

 tion, and not separately ; but they are neverthe- 

 less essentially distinct. They are selection and 

 crossing. Pure selection, operating on material which 

 is not the immediate result of a cross, modifies the 

 form of an animal or plant, and leaves it different 

 from what it was when the selection began ; some- 

 thing has been added or taken away ; something 



