68 THE DATA OF BIOLOGY. 



follows from tlie persistence of force, that each portion of 

 mechanical or other energy which an organism exerts, im- 

 plies the transformation of as much organic matter as con- 

 tained this energy in a latent state. And on the other hand, 

 it follows from the persistence of force that no such trans- 

 formation of organic matter containing this latent energy 

 can take place, without the energy being in one shape or 

 other manifested. 



