ORIGIN OF LIFE, SEX, SPECIES, ETC. 229 



the lifetime of the organism. The reproduction of 

 fertile offspring has until lately been regarded as 

 the test by which it is evidenced that both of the 

 organisms which entered into the act by which the 

 fertilized ovum is produced belong to the same 

 species. The fertilized ovum must contain all the 

 potencies out of which the essential properties of 

 the subsequent organism arise. For although the 

 environment undergoes ever so many changes, it 

 cannot make "grapes to grow on thorns," or "figs 

 on thistles," without resort to grafting or budding, 

 and the artificial changes worked by man's ingenu- 

 ity are not discussed in this place. 



While, then, as above stated, the nature of the new 

 organism is entirely determined by the mixture of 

 reproductive cells which initiates it, the material 

 for it must be drawn from the environment by 

 absorption and assimilation. 



When the mind attempts to follow the process of 

 absorption and assimilation, the assumption of an 

 excess of energy in the living, absorbing, assimilating 

 entity becomes inevitable. If the energy within 

 this latter were equal only to that in the environing 

 materials, then no balance of force would remain to 

 start the changes involved in absorption or assim- 

 ilation. If the excess of energies resided in the 

 environing materials, then these would tend to ab- 

 sorb, transform, or assimilate the living entity. 

 There remains, then, only the alternative first stated. 



For motion is always in the direction of greatest 



