MANUAL OF NATURE STUDY. 95 



take to our homes ? What is necessary to be done 

 before the sheep's back will furnish our clothing, or 

 the tree our furniture ? Then what must be done 

 before the elements of the ground will nourish our 

 bodies? As the manufacturer and tailor change 

 the wool into clothing, and the cabinet maker the 

 trees into furniture, so do plants imbibe the elem- 

 ents of soil and other foods for animals to eat. 

 How do plants accomplish such a wonderful task ? 



1. By keeping the original rocks moist, and by 

 decay of leaves, mosses, etc., producing carbonic 

 acid which dissolves the rocks, and thus gives more 

 soil for a more luxurious growth of vegetation. 



2. By breaking rocks in pieces by the penetrat- 

 ing power of roots. 



3. By holding moisture back along the sides of 

 hills to prevent its running away in floods, until 

 the plant life can have time to utilize the food dis- 

 solved in it. 



As to manner of food storage, plant substance 

 and seed factories, see topics already written 

 in previous pages of this book. What have 

 animals done to repay the plant kingdom for 

 all this labor ? Take the fish-worm for example. 

 The fish-worm, or earth-worm, has so burrowed or 

 channelled the ground that it is difficult to find a 

 place where they have not been. 



