130 A NEW THEORY OF EVOLUTION. 



ganism ; for while the organ thus reinforced 

 develops abnormal size, strength, keenness, 

 or sensibility, as the case may be, the organs 

 despoiled fail to attain normal development. 



The energy of every life-force is limited, 

 and if one organ benefits by appropriating 

 a portion of the energy properly belonging 

 to another, the advantage is not a clear 

 gain to the animal, but merely a trans- 

 ference of energy from one organ to 

 another. Athletes sometimes break down 

 under excessive training : they have by ex- 

 cessive use exhausted their strength or the 

 elasticity of the muscles excessively used. 



When only certain parts of the body are 

 developed by excessive use, other parts are 

 abnormally weak. The senses of touch and 

 hearing become highly developed in the 

 blind, by transference of vital energy from 

 the disused organs to those called into ex- 

 cessive use. If a cow yields milk largely, 

 she will not put on flesh, and hence, as a 

 rule, good milch cows are thin. On the 

 other hand, the arm of the Indian fakir 

 becomes withered by persistent disuse. 



But all such modifications are differences 

 only in degree, and do not disclose any 

 tendency towards the specific variation that 

 constitutes a new species. Moreover, the 



