28 Dynamic Evolution 



expenditure of other energy. The mere feed- 

 ing of an ordinary horse will not make him 

 into a 2 : 10 trotter. What energy was ex- 

 pended, and how was it expended to produce 

 this 2 : io trotter? 



We know of but one process by which 

 available energy can be concentrated in a 

 living organism, and that is by expending 

 energy through the organs within which it is 

 intended that the concentration shall take 

 place. This is exercise, and the kind of 

 energy stored is identical with the kind of 

 work performed. We use it on the track and 

 in the gymnasium to concentrate energy in 

 the muscles, and in the schools to concentrate 

 it in the brain. We may not know the details 

 of the process by which the concentration is 

 brought about, but we know the fact that 

 such concentration results from such expendi- 

 ture. We also know that the available 

 energy existing in a living organism will 

 decline (become dissipated or leak away) if 

 not continually replenished by exercise. The 

 idle animal becomes the weak animal. 



