42 PRINCIPLES OF BREEDING. 



erties that they have constantly fostered variation in 

 favor of the one at the expense of the other until the 

 milking quality in many families is nearly bred out. 

 It was not so formerly — thirty years ago the Short- 

 horns (or as they were then usually called, the Dur- 

 hams) were not deficient in dairy qualities, and some 

 families were famous for large yield. By properly 

 directed efforts they might, doubtless, be bred back to 

 milk, but of this there is no probability, at least in Eng- 

 land, for the tendency of modern practice is very strong 

 toward having each breed specially fitted to its use — 

 the dairy breeds for milk and the beef breeds for meat 

 only. The requirements of the English breeder are in 

 some respects quite unlike those of New England farm- 

 ers — ^for instance, as they employ no oxen for labor 

 there is no inducement to cultivate working qualities 

 even, in connection with beef. 



As an illustration of the effect of habit, Darwin* cites 

 the domestic duck, of which he says, " I find that the 

 bones of the wing weigh less, and the bones of the leg 

 more, in proportion to the whole skeleton, than do the 

 same bones in the wild duck ; and I presume that this 

 change may be safely attributed to the domestic duck 

 flying much less and walking more than its wild parent." 

 And again, " not a single domestic animal can be named 



* In his Origin of Species. 



