THE ORIGIN OF LIFE 175 



whereas vital action is of the reflexive or immanent type. 

 Mechanical action, for example, is intermolar {i.e. an exchange 

 between large masses of inorganic matter) ; physical action is 

 intermolecular ; chemical action is interatomic ; while in radio- 

 active and electrical phenomena we have intercorpuscular ac- 

 tion. Hence all the forms of activity native to the inorganic 

 world are reducible to interaction between discontinuous and 

 unequally energized masses or particles. Always it is a case of 

 one mass or particle operating upon another mass or particle 

 distinct from, and spatially external to, itself. The effect or 

 positive change produced by the action is received into another 

 unit distinct from the agent or active unit, which can never be- 

 come the receptive subject of the effect generated by its own 

 activity. The living being, on the contrary, is capable of oper- 

 ating upon itself, so that what is modified by the action is not 

 outside the agent but within it. The reader does not modify the 

 book, but modifies himself by his reading. The blade of grass 

 can nourish not only a horse, but its very self, whereas a 

 molecule of sodium nitrate is impotent to nourish itself, and 

 can only nourish a subject other than itself, such as the 

 blade of grass. Here the active source and receptive subject 

 of the action is one and the same unit, namely, the living 

 organism, which can operate upon itself in the interest of its 

 own perfection. In chemical synthesis two substances interact 

 to produce a third, but in vital assimilation one substance is 

 incorporated into another without the production of a third. 

 Thus hydrogen unites with oxygen to produce water. But in 

 the case of assimilation the reaction may be expressed thus: 

 Living protoplasm plus external nutriment equals living pro- 

 toplasm increased in quantity but unchanged in specificity. 

 Addition or subtraction alters the nature of the inorganic 

 unit, but does not change the nature of the living unit. In 

 chemical change, entelechy is the variant and matter is the 

 constant, but in metabolic change, matter is the variant and 

 entelechy the constant. ''Living beings," says Henderson, 

 "preserve, or tend to preserve, an ideal form, while through 



