THE HORSE-BREEDINQ. 535 



horse, may consume more feed than his mate, and yet if labor 

 is the test of value, he may do enough more work to pay the 

 better price for his feed, and vice-versa. The question is not 

 so much as to amount consumed, but as to what use it makes 

 of it in producing flesh or force. The art of breeding we may 

 say has for its ultimate end, the development of animals in the 

 lines that will yield best returns for feed and care given. 



Heredity a Fundamental Principle. The foundation 

 of successful breeding rests on the law of heredity. That such 

 a law exists in the order of nature is to be concluded from the 

 regularity with which animals in a state of nature produce their 

 kind. The wolf produces only a wolf, with none of the quiet, 

 gentle traits of a lamb or a pet dog. The wolf of to-day is es- 

 sentially like that of fifty or a hundred years ago. The animals 

 on the monuments of Egypt are essentially the same as those 

 now found along the Nile. 



When, however, man comes into the business of breeding, or 

 controlling connections of animals, we find the types of suc- 

 cession begin to vary. The wolf bred to the dog produces an 

 animal in some degree like a wolf, but modified by the character- 

 istics of the dog. We call the produce a mongrel. If we cross 

 this mongrel again with a wolf, the produce is more wolfish than 

 the mongrel, and if crossed with the dog many times in succes- 

 sion, we may, in the course of years, circumvent the law of 

 nature that would produce a wolf from a wolf. Every time the 

 cross is made with the dog, the wolfish tendency is weakened, 

 and the probability of the offspring taking the fixed type of the 

 dog is increased. But so strong is the law of heredity, and so 

 firmly has the wolf's nature been fixed by centuries of wolf-breed- 

 ing, that with all man's efforts to destroy that tendency to pro- 

 duce an animal of the wolf-kind, the wolfish traits are ever 

 cropping out. 



Atavism Beneficial. This reversion to a type of a former 

 ancestor is called atavism. It is at once a difficult thing to con- 

 trol, and at the same time a beneficial thing, when we have so 

 long a line of desirable ancestry established by long-continued 

 good selection as that the chances of breeding like some former 



