XII 



SPECULATIONS 



IT is not the purpose of this book to deal fully 

 with the principles of stock-breeding, but some 

 phases of the question raised by the preceding 

 chapters might be referred to with interest at 

 least. It cannot have escaped the notice of any 

 one who has read the last few chapters how large 

 have been the parts played by crossing and in- 

 breeding in bringing our British breeds of cattle 

 to their present position. At the same time, it 

 must be admitted that it is not clear that every- 

 thing accomplished has been due to the action of 

 those two factors. There may still be something 

 more there may still be the constantly accumu- 

 lating change which Darwin believed in, although 

 it is hard to think that changes which formerly 

 took thousands and thousands of years may now 

 be induced by man's action in two or three 

 centuries ; and there may also be De Vries's 

 mutations or organic "jerks," the results of 

 changed conditions in food, climate, or any other 

 form of environment. So far these questions 

 must be left undecided ; but it seems impossible 



136 



