VI PREFACE. 



ized in the British Islands, numerous varieties present 

 themselves, to which we apply the term Breeds. The 

 characters of species may have been imprinted by ori- 

 ginal organization, or may have been the result of laws 

 of organic development and change, of whose nature 

 and operation we are ignorant. The characters which 

 distinguish varieties are those which may reasonably be 

 ascribed to known agencies, as climate, and the supplies 

 of food. The differences of character, indeed, produced 

 by agencies of this kind, may be very great; and, in 

 the case of many animals, the naturalist may be left in 

 doubt, whether the differences observed are the result 

 of original organization, or of more recent changes. 

 But however species may have originated, or varieties 

 have been produced, all animals submitted to domesti- 

 cation are subject to modifications of size, form, and 

 other characters, dependent on the conditions under 

 which they are reared ; and by breeding, we can com- 

 municate the distinctive properties of parents to the 

 progeny. 



In the rural economy of this country, a high degree 

 of importance is to be ascribed to a knowledge of the 

 distinctive characters of Races or Breeds. Much of 

 the profit of the owners depends upon adapting the 

 breed of any animal to the circumstances in which it 

 is to be placed. By rearing, for example, a breed of 

 large and delicate oxen, in a country unsuited, from its 

 natural or artificial productions, to maintain it, we 

 incur the hazard of loss in various wavs ; while, on the 



