34 A TREATISE ON HORSE-BREEDING. 



EXTENT OF HEREDITARY INFLUENCE. 



I have spoken of two forces that, in their 

 effects, appear to be diametrically opposed to 

 each other heredity, which makes of every in- 

 dividual the sum, or aggregation, of that which 

 has preceded it, and evolution or spontaneity, 

 which constantly tends to give to animal life 

 new forms and to each individual peculiarities 

 which belong to it alone. Of these heredity is 

 unquestionably the stronger force, because, as 

 I have before remarked, when uniformity has 

 once been established the general principle that 

 like produces like finds very rarely an excep- 

 tion. In fact the influence of heredity is always 

 present, and in the reproduction of animal life 

 never fails to assert itself in a greater or less 

 degree. Every living thing brings forth young 

 after its own kind in some cases the exact 

 counterpart of the parent, and in others slightly 

 modified; but always showing more or less of 

 the parent type. Men do not gather grapes of 

 thorns nor figs of thistles, neither do Short-horn 

 COW T S bring forth buffalo calves nor draft mares 

 produce thoroughbred race horses. Hence, al- 

 though we may frequently meet with very strik- 

 ing differences between the parents and the 

 progeny, yet a moment's reflection will show 

 us that the points of resemblance are always 

 very much greater than those of difference. 



