MICROORGANISMS AND SOIL FERTILITY 77 



action of earthworms and the roots of the higher plants. 

 The ordinary concept of the soil, that it is an inert mass 

 of mineral matter, is therefore far from the fact. It is 

 filled with the most varied kinds of living things of micro- 

 scopic size, the work of which is as vital to animal existence 

 as it is to the green plant. The farmer must care for these 

 tiny inhabitants of the soil as well as for his crops and 

 animals. 



