APPLICATION OF THEORY TO PRACTICE. 83 



The laws of variation, on the other hand, are 

 always to be kept in mind. Variations are, 

 perhaps, rare ; when they occur they doubtless 

 are not of a radical type in our old and well- 

 established varieties. But variations do occur, 

 and occur sufficiently often, and are sufficiently 

 definite to merit careful attention and to en- 

 courage the thoughtful breeder to make the 

 most of them. In the more recently improved 

 breeds in the grade and " scrub" and crossed 

 cattle variation takes place more often. But 

 however these laws may be regarded as ab- 

 stract and theoretical, the practical experience 

 of almost any observant breeder will quickly 

 convince the most skeptical that it is of the 

 utmost importance that these laws should be 

 understood, not perhaps in the sense that every 

 breeder should be able to define and explain 

 them, but rather that however formally unrec- 

 ognized, yet that they should be practically 

 acted on. The difference between the man 

 who weighs well the rules and laws of Nature 

 in the light of his experience, with a full 

 knowledge of all that has ever been written on 

 the subject, and he who, recognizing simply that 

 a bull breeds like himself in proportion as he 

 is vigorous, lusty, and well bred, selects in con- 

 sequence a bull of these qualities, and of the 

 highest degree of excellence obtainable, to use 

 on his herd of fine cows, is much the same as 



