56 



JAMES M. SHERMAN 



A study of the data fails to give any evidence that the proto- 

 zoa act as a limiting factor upon the soil bacteria. In general 

 it will be seen that curves representing the numbers of bacteria 

 throughout the period would run nearly parallel in the different 

 soils. The difference in the numbers of bacteria in soils with 

 and without protozoa was apparent from the start, which fact 

 indicates that the phenomena is due to a difference in the bac- 



TABLE XI 

 The development of bacteria in soils containing protozoa and in soils free of protozoa 



A = soil without protozoa. 

 B = soil with protozoa. 



terial flora and not to the protozoa. There was no evidence 

 that a detrimental factor developed during the latter part of 

 the period. 



Discussion 



An examination of the data presented in the foregoing experi- 

 ments reveals the fact that in all of the tests the soils which 

 contained protozoa gave lower bacterial counts as determined 



