I 



The dwellers in the soil 



63 



Summary. The soil is full of living things, some 

 large like earthworms, others very small. Earthworms 

 are very useful: they make burrows in the soil, thus 

 allowing air and water to get in : they drag in leaves 

 and they keep on covering the surface with soil from 

 below. Besides these and the other large creatures, 

 there are micro-organisms so small that they cannot be 

 seen without a very good microscope: they live and 

 breathe and require air, water and food. Some are very 

 useful and change dead parts of plants or animals into 

 valuable plant food. Almost anything that can be 

 consumed by fire can be consumed by them. Others 

 are harmful 



