Analogies Concerning Life 147 



generated during the acceleration-period by 

 a pulse of radiation which travels with the 

 speed of light, being maintained during the 

 steady-motion period by a sort of inertia as 

 if in accordance with the first law of 

 motion, and being destroyed only by a 

 return pulse of re-radiation during a 

 retardation-period when the moving charge 

 is stopped or diverted or reversed all this 

 can hardly be fully explained until the 

 intimate nature of an electric charge has 

 been more fully worked out ; and the 

 subject now trenches too nearly on the 

 more advanced parts of Physics to be use- 

 ful any longer as an analogue for general 

 readers. 



Indeed it must be recollected that no 

 analogy will bear pressing too far. All 

 that we are concerned to show is that 

 known magnetic behaviour exhibits a very 

 fair analogy to some aspects of that still 

 more mysterious entity which we call 

 " life " ; and if anyone should assert that all 

 magnetism was pre-existent in some ethereal 



