8 MICROORGANISMS IN SOILS AND WATER BASINS 



a mass of living matter as do the bacteria ; their actual number, as deter- 

 mined by the plate method, may vary from a few thousand to several 

 hundred thousand per gram of soil. The significance of these results is 



TABLE I. INFLUENCE OF SOIL TREATMENT ON NUMBER 

 OF MICROORGANISMS 



From Waksman (945). 



* In thousands per gram of soil as determined by plate method. 



TABLE 2. INFLUENCE OF GROWING PLANTS ON NUMBER 

 OF MICROORGANISMS IN THE SOIL 



