88 THE GARDEN OF EARTH 



last word means that it has to get rid, through its skin, 

 of water not wanted for its own use. 



Would you have thought of a tree being obliged to 

 breathe? But indeed it must. It cannot live without 

 breathing. Like a man, it must have oxygen gas, or 

 it will die of suffocation ; yes, of actual slow suffocation. 

 A tree breathes day and night ; summer and winter. 



A man breathes by means of his lungs. But a tree 

 has no lungs; and it breathes in all its parts that are 

 actively alive its roots, its green stems, its seeds, its 

 fruits. If the roots cannot find enough air in the soil, 

 then the whole tree suffers. It also breathes by its 

 leaves. 



When a man's lungs receive the air which he has 

 drawn in, they make use of it for his body. A kind of 

 burning goes on within him, much as when fire burns 

 away wood. The oxygen of the air is united with some 

 of the carbon of his body, to make carbonic-acid gas ; 

 and this is poured out again into the atmosphere. It 

 has to be got rid of quickly ; for if not, the man would 

 die. 



And the same thing goes on in a tree, in any kind of 

 plant. There too, the oxygen of the air, which has 

 flowed in through countless little pores, is united with 

 some of the carbon of the tree, and carbonic-acid gas 

 is formed, ready to be poured forth into the atmosphere. 



V AND THE WORK OF A LEAF 

 Thus far the tree does much the same as we do. Here 



we come to a difference. 



It has to digest, as well as to breathe. That is, it has 



to take in food, and to make that food a part of itself. 



