SYSTEMS OF BREEDING 615 



an almost unlimited extent by the blood of a single animal, - 

 in practice, generally that of the sire. It is a method not so 

 much of originating excellence as of making the most of it when 

 it does appear, and it is not too much to say that a large pro- 

 portion of the really great sires have been strongly inbred. 



An inbred animal is of course enormously prepotent over 

 everything else. Its half of the ancestry, being largely of iden- 

 tical blood, is almost certain to dominate the offspring. Inbreed- 

 ing is, therefore, recognized as the strongest of all breeding, 

 giving rise to the simplest of pedigrees, an advantage quickly 

 recognized when we recall the law of ancestral heredity. In this 

 respect it is all that line breeding is and more. 



A second advantage is that successful associations of char- 

 acters are preserved intact and not shattered by the infusion of 

 new strains. If the breeder were dealing with but a single char- 

 acter he could readily find its equal, and there would be little 

 need for inbreeding ; but even if breeding for but a single utili- 

 tarian character, he always has at least two others, vigor and 

 fertility, which must be included in selection. In practice he has 

 many more, and a single individual that contains all or most of 

 them in a high degree is a veritable bonanza ; naturally the 

 temptation is to make the most of an opportunity which is none 

 too frequent in the breeding business. 



All things considered, no other known method of breeding 

 equals this for intensifying blood lines, doubling up existing 

 combinations, and making the most of exceptional individuals 

 or of unusually valuable strains. 



Disadvantages of inbreeding. Clearly, however, this is not a 

 gun to u hit the bear and miss the calf." This "doubling up" 

 process, this intensifying of characters, increasing their prospects 

 from possibility to probability and afterward to certainty, works 

 exactly the same for one character as for another ; it affects all 

 characters of tJic individuals involved, bad as well as good; and 

 so it is that this method, which is applicable to both plant and 

 animal breeding, and which aims at making the greatest use 

 possible of our most valuable possessions, has been followed 

 alike by the most strikingly successful results and by the most - 

 stupendous disasters that ever overtook the breeding business. 



