STUDIES ON SOIL PROTOZOA AND THEIR RELATION 

 TO THE BACTERIAL FLORA. I^ 



JAMES M. SHERMAN 



From V4te Bacteriological Laboratories of the Wisconsin Agricultural Experiment 



Station, University of Wisconsi7i 



I. INTEODUCTION 



The occurrence of protozoa in soil 



The knowledge that protozoa occur in soil dates back nearly 

 as far as does the science of microbiology, but it is only recently 

 that specific studies have been directed at the micro-fauna of 

 the soil. Miiller (1887) reported studies concerning some soil 

 protozoa which he thought played a part in the destruction 

 of organic tissue, and thus were to be considered as important 

 agents in the formation of humus. Celli and Fiocca (1894) 

 studied the protozoa of the soil and described several forms of 

 amoebae obtained from this source. Beijerinck (1896) described 

 an amoeba which occurred in his cultures of nitrifying bacteria;, 

 and later (1901) called attention to a variety of amoebae, monads 

 and infusoria which appeared in cultures with Azotobacter. 

 Frosch (1909) isolated a number of saprophytic amoebae from 

 garden soil similar to those found in the intestinal tracts of ani- 

 mals. Tsujitani (1908), likewise described some amoebae which 

 occur in soil. Hiltner (1907) noted many types of protozoa 

 which appeared in cultures made from soil, and stated that 

 these organisms certainly do not play an unimportant role. He 

 noted the presence of various ciliates, flagellates, and amoebae, 

 some of which he said were often present in unusually large 

 numbers. Stormer (1907) also studied the protozoan fauna, and 

 demonstrated that the soil contains a considerable number of 

 these organisms, especially amoebae. 



1 Presented at Seventeenth Annual Meeting of the Society of American Bac- 

 teriologists, Urbana, 111., December 29, 1915. 



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