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ties belonging to different families or breeds of the same species, and that 
the adaptedness of animals to particular localities or purposes, depends 
on these constitutional traits. A neglect of this principle has often led 
to serious mistakes. A breed which succeeds well under a mild climate, 
. 
and on a soil producing abundance of nutritious grass, has proved 
wholly unprofitable when transferred to a different region—a result which 
might have been anticipated under a proper knowledge of the natural 
tendencies of the stock. Again, breeds of cattle whose distinguishing 
quality is the accumulation of fat, have failed to meet the expectations 
of some who, without understanding their characteristics, have adopted 
them for dairy purposes. 
Another important principle is, that the characteristics of races or 
breeds, are in some degree under the control of man. For instance, a 
breed of sheep may produce a fleece of combined wool and hair, the 
proportions varying in different individuals. By selecting for propagation 
those which produced most wool and least hair, the growth of the latter 
may, in time, be wholly displaced by the former. So in reference to 
other qualities; any particular one may be increased by selecting and 
breeding from animals in which it is most strikingly manifested. But it 
should be borne in mind, that excellencies are more or less accompanied 
by defects, and critical judgment is required to obtain animals which pos¬ 
sess the desired properties free from imperfections which lessen their 
value. 
There is, therefore, not only a diversity in what may be called the 
original or natural qualities of animals, but there is also a great differ¬ 
ence in the same race in a natural state and when subjected to artificial 
influences. It is true that in a strictly natural state—that is, a state of 
entire liberty—nature might be expected to inspire animals with such 
instincts as would perpetuate the race in the greatest perfection, having 
reference to the circumstances in which they are placed. But our domestic 
animals are not in this situation ; they are more or less subject to man's 
will; he desires to develop in them such properties as will render them 
most subservient to his wants. It is obvious, that animals thus situated 
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are deprived, to some extent, of the advantages of their natural instincts, 
and that hence, unless the art of man is properly exercised on them, they 
Trould be likely to degenerate from their primitive condition. 
