GENERAL PRINCIPLES OF BREEDING. 49 



results manifested from long-continued breed- 

 ing in-and-in which is the very opposite of 

 violent out-crossing; and yet all experience 

 proves this to be true. 



The space that can be devoted to a discussion 

 of this branch of the subject will not admit of 

 an elaborate investigation of the principles of 

 genesis by which this apparent contradiction 

 is explained. The majority of my readers are 

 more concerned with facts and results than with 

 theories and philosophical abstractions. But, at 

 the risk of giving more of theory than will be 

 relished, I will venture to state that, in order 

 to produce a sexual union which shall be fruit- 

 ful, and call into life a new organism, accord- 

 ing to the opinion of most scientists, it is essen- 

 tial that the sperm-cell and the germ-cell, 

 which, united, form the source of life to the 

 new being, shall each proceed from a different 

 organism; and that breeding in-and-in, as usu- 

 ally practiced being the selection of individ- 

 uals of as nearly as may be a similar organi- 

 zation, with the avowed purpose of creating 

 uniformity of character will, in the course of 

 time if not counteracted by opposing influences, 

 produce such a unity of organism in the mem- 

 bers of a given family as will result in a loss of 

 that differentiation which appears to be neces- 

 sary to insure the fusion of the sperm-cell of 

 the one with the germ-cell of the other. 



