THE NATURAL HISTORY OF REST 325 



and yet whenever we look at these water-mites they are 

 dashing about with headlong velocity, expending energy 

 without apparent exhaustion, continually rushing and 

 hustling, as if they were going to catch a train. That 

 they ever catch anything we do not know. We suppose, 

 indeed, that there is some microscopic food in the water, 

 and that the mites sometimes rest when we are not looking 

 at them, but they have always seemed to us fine instances 

 of what is in some degree true of all living creatures 

 they have an extraordinary power of accumulating energy, 

 and of accumulating it acceleratively. We know that 

 when we heat a bar of iron, or charge a Ley den jar, or 

 in any other way pass energy into an inanimate system, 

 the transfer becomes more difficult as we proceed ; there is 

 more and more tendency to the dissipation of the energy 

 accumulated, and there are effects retardative of further 

 transfer. But, as Prof. Joly points out, it is the opposite 

 with living creatures, and this is their great dynamic 

 peculiarity. They have extraordinary powers of storing 

 energy, and on the strength of their stores they may go 

 on without food or rest for many days. It is a realisation 

 of this power which leads many to deny the claims of 

 rest, and to forget that living on capital has its limits. 

 But although such periods of defiance may be happy and 

 brilliant, it is a perilous habit. 



When we contrast the animate and the inanimate after 

 this fashion, there rises in the mind the remarkable fact 

 that the sublimest examples of unrestingness are afforded 

 by the movements of the heavenly bodies, and of the 

 earth itself. For how many millions of years have all 

 these revolutions been going on, without haste, without 

 rest ? And what of that mysterious, unceasing movement 

 of our whole solar system towards an unknown goal in 

 space ? But the point is, we suppose, that these heavenly 



