CHAPTER II 

 OXIDATION LIFE PLANTS AND ANIMALS 



A MAN who is alive differs from a man who is dead inasmuch 

 as he is constantly performing movements, not necessarily of 

 his whole body from place to place, or even of his limbs, but 

 movement of his chest, by which air is drawn into his body, 

 and movement of his heart, by which blood is circulated 

 throughout his body. So long as these two movements go on 

 the man is alive; when they have both stopped the man is dead. 

 A certain amount of force is required to suck air into the lungs 

 and to pump blood throughout the body ; that is, a certain 

 amount of energy has to be used to do this work. When a 

 man is doing manual labour a large amount of additional 

 energy is being used to accomplish the work he has to do. 

 Thus whether the man is at rest or at work, energy is being 

 expended so long as he is alive. 



A piece of coal consists of carbon and hydrogen united with 

 one another and with other elements to form complex chemical 

 substances. If a piece of coal is lighted, the carbon and 

 hydrogen are separated by the breaking up of the complex 

 arrangement of elements, and unite with the oxygen of the air to 

 form carbonic acid and water. This breaking up of the complex 

 substances of the coal by the union of the carbon and hydrogen 

 with oxygen sets free energy, kinetic energy, as it is called, 

 in the form of heat and light, and so intense is the heat that we 

 say the coal "burns." The energy thus set free may be used 

 in many ways to do work as it is in a steam-engine. Energy 

 existed in the coal before it was lighted, having been stored up 

 as "latent energy" when the elements were knitted together 

 into complex compounds by the growth of the living tree in a 



