8 SOILS AND PLANT LIFE 



When wheat is received at the mills, it is run between 

 great steel rollers, and it then passes through a long series 

 of processes until it is separated into flour, bran, middlings 

 and various other products. 



We may compare the changes which take place in a 

 decaying plant with those which take place in the wheat 

 as it passes through the mill, but we find a difference. 



Fig. 3. — The cyde from plant to plant again. 



The products of the wheat can not be gathered together 

 again to make the kernels from which they came, whereas 

 in Nature the plants are broken down and separated by 

 the molds and bacteria into simple compounds, which 

 are taken up by roots and finally made again into living 

 plants. The drawing above will fix in our minds better 

 than words how this comes about. 



6. The Part Animal Life plays in making and mixing 

 Soils. — A plant may be eaten by an animal. A part 



