PRINCIPLES OF BREEDING. 171 



on all sides, both in the lower animals and in man. Cer- 

 tain families have certain peculiarities or habits, good or 

 bad, that are directly traceable to their ancestors ; that 

 is, animals bred true to a given idea or type for a long 

 time acquire fixed characters or peculiarities, which they 

 are capable of transmitting unimpaired to their offspring. 



The law of heredity is, however, only true in a general 

 sense. It is not absolute ; if it were, the improvement of 

 live stock would be impossible. Certain other natural 

 tendencies are constantly active to modify the law of 

 heredity. 



Atavism, or Reversion, is the name given to qual- 

 ities or habits in the offspring which were not possessed 

 by the immediate parents, but which were possessed by 

 some remote ancestor. This law of atavism, or tendency 

 to go back to an original type, is familiar to all breeders, 

 and frequently causes annoyance, particularly where fine 

 points in breeding are regarded as important. Many in- 

 stances are recorded in the various herd-books of the ap- 

 pearance of calves with a color totally different from that 

 of their immediate parents, and the appearance of an ani- 

 mal with horns is a quite common occurrence among the 

 recognized hornless breeds of cattle. 



Variation is a tendency in the offspring to be un- 

 like their parents. It is by virtue of this law of variation, 

 which is readily influenced by artificial conditions, that 

 rapid changes in types may be effected and new breeds 

 formed. 



The great gain in maturity and meat-producing qual- 

 ities of certain breeds of cattle is due in a great measure 

 to better methods of feeding, in connection with greater 



