82 THE GARDEN OF EARTH 



III How MANY LEAVES? 



The sap, having reached the boughs, passes into the 

 twigs, and thence onward into each separate leaf. 



For this purpose it has climbed the trunk that it 

 may get to the leaves. They have a great task to 

 carry out, which they could not possibly do without 

 the raw sap to manipulate. 



Each leaf by itself may be regarded as a small work- 

 shop ; this has been said earlier. And the " crude sap " 

 brought to it by the channels of trunk and branches is 

 as the " raw material " brought to a manufactory. 



" Pig-iron," for instance, is taken to great ironworks, 

 to be there transformed by many complicated methods 

 into all kinds and varieties of iron and steel goods. 

 Or, again, a different class of raw materials may be 

 conveyed to a soda manufactory, and after many pro- 

 cesses the finished article, soda, is produced for uses 

 innumerable. 



In like manner the raw sap is brought to the leaves 

 of a tree, to be transformed into many diverse substances, 

 needed by the tree itself for its own use, and needed 

 also by human beings. 



These " workshop " leaves are always green, except 

 when they first open out in early spring and when they 

 fade in autumn. In the spring many of them show 

 pink and salmon tints, but that is before they begin 

 their real business. And in the autumn they often 

 turn yellow or red, but that is when their task is done. 

 The life of a leaf is both short and busy. No idlers are 

 they, these useful little friends of ours. 



