270 DECOMPOSITION 



energy used in food manufacture are returned in useful 

 form again to the air and the soil from which they were 

 taken. In the ordinary course of nature there is little or 

 no disturbance of the balance in a given area. Only 

 where man or fire or some other accident (volcanic) in- 

 tervenes is there any considerable departure from the 

 regular cycle. 



