20 THE STOBY OF THE PLANTS. 



also breathes — that is to say, takes oxygen into 

 his lungs. Within his body that oxygen onco 

 more unites with the carbon and the hydrogen, 

 and is given out again in union with them as 

 carbonic acid and water. And the energy in the 

 plant food, thus set free within his body, takes 

 the form of animal heat and animal motion — 

 just as the energy set free in the locomotive 

 takes the form of heat and visible movement. 

 Animals are thus the absolute converse of 

 plants ; all that the plants did, the animal 

 undoes again. 



Briefly to recapitulate this rather dry subject, 

 — the plant is a mechanism for separating oxygen 

 from carbon and hydrogen, and for storing up 

 sun-energy. The animal is a mechanism for 

 uniting oxygen with carbon and hydrogen, and 

 for using the stored-up sun- energy as heat and 

 motion. 



And now you can see why it is so absurd to 

 ask, "Which came first, the plant or the animal? 

 You might as well ask. Which came first, the 

 coal or the fire? All the living material in the 

 world was first made and laid up by plants. 

 They alone have the power to make living or 

 energy-yielding stuff out of dead, and inert 

 water or carbonic acid. They are the origin 

 and foundation of life. Without them there 

 could be no living thing in the universe. It 

 is in their green parts alone that the wonderful 

 transformation of dead matter into living bodies 

 takes place ; they alone know how to store up 

 and utilise the sunshine that falls upon them. 



