VARIATION. 107 



The development of special characters in our do- 

 mestic animals, and their consequent improvement in 

 a particular direction, is apparently limited by the ten- 

 dency to diverse variations, from the increased sensi- 

 tiveness of the organization to the influence of modi- 

 fying agencies, and the defective equilibrium of the 

 organization arising from the excessive predominance 

 of a single character. If a variation in a special direc- 

 tion is made at the expense of constitutional vigor, 

 integrity of the nutritive organs, and fecundity, it be- 

 comes an abnormal character that cannot be perpetu- 

 ated. 



