THE SCIENCE OF BREEDING. 61 



Experience is of as much value in this matter as in any other, 

 yet there are certain general principles which inexperienced persons 

 can understand, and by following them closely cannot go far wrong 

 even in first essays. 



THE THEORY THAT " LIKE PRODUCES LIKE." 



It is claimed that " like produces like." This is true, but equally 

 so of the bad as of the good, and a thorough appreciation of what 

 constitutes similarity, and to what extent this is desirable, is ab- 

 solutely necessary for the successful application of this theory to the 

 production of dogs with desirable characteristics. As formerly 

 understood, like to like meant nothing more than the mating of one 

 good field performer with another, but, as we shall presently show, 

 this is only the alphabet of the theory, and such unions were more 

 liable to produce worthless than good progeny. 



In the first place blood was not regarded, and in this more in- 

 telligent age it is hardly necessary to say blood is of the highest 

 importance. Dogs of entirely different strains were bred together, 

 and when it is remembered that each breed has its individual 

 characteristics, such fixed and definite character being in fact the 

 very foundation of the claim to be considered a breed, it must be 

 apparent that the mating of individuals of different breeds produces, 

 as a primary result, a mingling of the different attributes of the 

 parents in their progeny. The tendency of all domesticated animals, 

 and especially of those which have been developed in what may be 

 called an unnatural degree, is to degenerate, and this inclination can 

 be overcome only by persistent strengthening of the cultivated 

 attributes, by continued breeding in the line which produced them. 

 To mingle different characteristics is, therefore, to introduce con- 

 flicting forces, each striving to assert its supremacy, and in a litter 

 thus bred there will naturally be great variation in the character of 

 individuals. Some will resemble one parent, some the other, and 

 others will differ from both. This resemblance and variation will 

 not be confined to physical form, but will extend to the higher 

 faculties also, and while some individuals may be as good as their 



