8 PRINCIPLES OF STOCK-BREEDING. 



When the entire energies of the system are acting 

 in a particular direction, as they must do to insure the 

 highest development of a single quality, there is no 

 residuum of force for the development of other quali- 

 ties that are not strictly correlated with the one that 

 is made dominant. 



The modern art of breeding is founded on the 

 practice of the most successful breeders, and its rules 

 have been almost exclusively empirical in their origin. 



The science of physiology, by explaining the prin- 

 ciples on which many of thes^ rules are based, has de- 

 fined the limits of their applications with greater ex- 

 actness, and suggested new fields for investigation. 



In its progress the art has, however, kept constant- 

 ly in advance of the allied science of physiology, which 

 it has aided in developing by presenting, in its definite 

 facts, the required data for successful scientific study. 1 



With the progress of knowledge, the unexplained 

 precepts of the art are gradually diminishing, and the 

 many theories that have been framed from partial 

 views of the truth must be replaced by consistent 

 principles of general application. 



The inferior quality of the live-stock on the farms 

 throughout the country shows that the relations of 

 the art of breeding to the practice of agriculture have 

 been too generally overlooked by farmers. 



Looking upon live-stock as a special interest, and 



1 Whewell remarks that "in all cases the arts are prior to the 

 related sciences. Art is the parent, not the progeny, of science : the 

 realization of principles in practice forms part of the prelude, as well 

 as the sequel, of theoretical discovery " (" History of the Inductive 

 Sciences," vol. i., p. 240). 



