H2 THE MECHANISM OF LIFE 



the cause of an organic action is an exciting energy from 

 without, either immediate, or stored up in the nervous system 

 from an external impression made at some previous epoch. 

 Actions which are not evidently reflex are merely delayed 

 reflexes; we have acquired the power of inhibiting, delaying, 

 or modifying the response to an external stimulus, so that the 

 same excitation may determine responses of very different 

 kinds according to the mood produced by previous impressions. 

 When carefully investigated, no action of ours is automatic; 

 every movement is determined bv impressions derived from 

 without. An action without a motive, that is without an 

 external determining cause, would be an action without reason. 

 In conclusion, we may formulate this general principle : 

 The energy of a living being is potential energy ; sensation* 

 represent the intervention of an external exciting energy which 

 provokes the response, i.e. the transformation of the potential 

 energy already stored in the organism into the actual energy 

 of motion and vital activity. 



