HOW PLANTS DBINK. 63 



chlorophyll. These the animal may afterwards 

 eat, either in the form of leaves like grass, or in 

 the form of seeds or fruits, like corn, rice, or 

 bananas. 



The tiniest primitive one-celled plant con- 

 tains protoplasm and chlorophyll (though a 

 few degenerate plants, like fungi, have none 

 of the living green-stuff, and can make nonejL 

 living material for themselves, but depenHTTike 

 animals, upon the industry of others). Every 

 living cell of every plant contains protoplasm ; a 

 cell without anyls dead and lifeless. Protoplasm, 

 in short, is the only living material we know; and 

 its life constitutes fne 

 compounded of it. 



Well, now you are in a position to see why 

 the farmer and the gardener attach so much 

 importance to the soil, and so little, apparently, 

 to the air and the sunlight. The reason is that 

 the air is everywhere ; you get it for nothing ; 

 but the soil costs money, and, when cultivated, 

 it requires to be supplied from time to time with 

 fresh stores of the particular materials the plants 

 take from it. 



Let me give two simple parallel cases. A fire 

 is made by the combination of two sorts of fuel 

 coal and oxygen. One is just as necessary for 

 fire-making as the other. But we buy coal dear, 

 and we neglect to take oxygen into consideration 

 accordingly. The reason is that oxygen exists 

 in abundance everywhere ; so we don't have to 

 buy it. If we paid a pound a ton for it, as we 

 do with coal, we should very soon remember 



