102 THE GARDEN OF EARTH 



until the morning. Yet their so doing may be of use 

 to the plant in the two ways named above. 



Leaves, as we have seen, are called upon to carry 

 out many and varied tasks. But of all that they have 

 to do, not one is more necessary for ourselves than the 

 wonderful way in which they transform the raw sap 

 into all kinds of food and other useful substances. 



A very remarkable part of the matter is that each 

 kind of plant should always make its own especial 

 material, and should always go on making it. Through 

 years, through hundreds of years, still plant after plant, 

 shrub after shrub, tree after tree, manufactures always and 

 only its own particular " brands," and never any others. 



Different plants may grow side by side, using the 

 same air, the same earth, the same water ; and yet the 

 " finished article " turned out by each is not the same. 



One kind brings forth poisonous berries. Another 

 brings forth a delicious fruit. Another brings forth a 

 remedy for illness. Another brings forth something of 

 use in our household work. Another brings forth that 

 which we need for clothing. But always, always, the 

 same thing is made by the same kind of plant. 



And this means that each plant uses for its work 

 exactly the right materials. It chooses out those sub- 

 stances, from the various supplies which travel to it in 

 air and in water. It refuses the wrong ones and keeps 

 the right ones, handing over the latter to the leaves — 

 its small workshops. And the leaves, busily toiling 

 through the few months of their brief existence, always 

 turn out that particular article which they and their 

 kind alone are able to produce. 



