120 Practical Farming 



bacterium is the smallest of known vegetable forms. 

 Many bacteria are barely within the reach of the highest 

 powers of the microscope, and it may be that there are 

 still smaller forms that play an important part in the 

 changes wrought in the soil, but so small as to be undis- 

 coverable. There are many sorts of these bacteria, some 

 being disease-making forms, and others of a beneficial 

 nature. But what we are here concerned with are the 

 forms that exist in the soil and work for the farmer there, 

 and also to arrive at a better understanding of the condi- 

 tions in the soil necessary for the welfare of these minute 

 plants whose work is always beneficial in agriculture. 

 Many of them vary so little in appearance that some as- 

 simie that all of them belong to one general species. But 

 whether this is true or not they have become so altered in 

 function that they are as really distinct as though of 

 entirely different species. Certain forms that do certain 

 work in the soil have been isolated and studied; the par- 

 ticular part they play has been definitely determined; 

 and it is evident that a study of these minute forms will 

 help us more toward the imderstanding of the work that 

 goes on in the soil, than any chemical analysis, which 

 destroys life, can ever do. 



When any organic matter, either animal 

 How Bacteria ^^ vegetable, is buried in the soil within 

 Work in the , r i , i ^ 



Soil reach of the atmosphere, the first thmg that 



takes place is what we call decay. This 

 decay, or the breaking down of the original tissues, is 

 carried on in the presence of oxygen and moisture, by 

 millions of these bacteria, whose special work is to reduce 

 the organic matter to its original elements. All organic 



