STUDIES ON SOIL PROTOZOA AND THEIR RELA- 

 TION TO THE BACTERIAL FLORA. 11^ 



JAMES M. SHERMAN 



From the Bacteriological Laboratories of the Wisconsin Agricultural Experiment 

 Station, University of Wisconsin 



VI, THE EFFECT OF VOLATILE ANTISEPTICS UPON SOIL PROTOZOA 



Introduction 



It is claimed by Russell and Hutchinson and their co-workers 

 that soils partially sterilized with volatile antiseptics are en- 

 tirely freed from protozoa. Hutchinson (1913) further claims 

 that the larger types of the soil protozoa are killed by the treat- 

 ment of soil with caustic lime. On the other hand, the results 

 reported by Gainey (1912) and b}^ Grieg-Smith (1911) indicate 

 that the application of such amounts of volatile antiseptics 

 as are used in practice does not exterminate the protozoa. Even 

 if it be acknowledged that some types of the soil protozoa are 

 able to resist the process of partial sterilization by antiseptics, 

 we must still consider the contention of Russell and Hutchinson 

 that the harmful factor is inactivated for a considerable period, 

 when not exterminated. Further, the possibihty exists that 

 the kinds of protozoa most detrimental to the bacterial flora 

 are pecuharly susceptible to the antiseptics. Since the greater 

 part of the protozoan fauna of the soil is inactive, the mere sur- 

 vival of certain types is not necessarily important, but the effect 

 of volatile antiseptics upon the active soil protozoa, on the other 

 hand, would appear significant. 



Experiments 



Tests were made of partially sterilized soils to determine the 

 number of protozoa and also the types. These tests were made 



^Continued from the Journal of Bacteriology, vol. i, no. 1, p. 35. 



165 



