182 JAMES M. SHERMAN 



19. The treatment of soil with carbon bisulphide at 37°C. 

 gives a very marked increase in the number of bacteria in the 

 soils treated. 



20. Sterilized soils which are reinoculated with normal soil 

 and with partially sterilized soil show no essential difference 

 in the numbers of bacteria which develop. 



21. Wlien volatile antiseptics are applied to sterilized soils 

 reinoculated with and without protozoa no difference is to be 

 noted between the behavior of the bacteria in the different soils. 



22. No evidence has been obtained which indicates that the 

 beneficial effect of partial sterilization is due to the elimination 

 of a biological factor which is harmful to the bacteria. 



Acknowledgment is due Professors E. G. Hastings, A. S. 

 Pearse and E. B. Fred of the University of Wisconsin, from 

 whom criticisms and suggestions have been obtained during the 

 progress of this work. 



LITERATURE CITED 



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 Centbl. Bakt. (etc.), Abt. 1, 19, 257-267. 



1897 Amoebenkultur auf festen Substraten. Centbl. Bakt. (etc.), 

 Abt. Z, 21, 101-102. 



1901 Ueber oligonitrophile Mikroben. Centbl. Bakt. (etc.), Abt. 2, 

 7, 561-582. 



Berliner, E. 1909 Flagellaten-Studien. Arch, fiir Protistenkunde, 15, 297- 

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BoLLEY, H. L. 1910 Conservation of the purity of soils in cereal cropping. 

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1913 The complexity of the micro-organic population of the soil. Sci- 

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1913 Cereal cropping: sanitation, a new basis for crop rotation, 

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BoTTOMLEY, W. B. 1911 Some effects of bacteriotoxins on soil organisms. 

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BuDDiN, W. 1914 Partial sterilization of soil by volatile and non-volatile anti- 

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Calkins, G. N. 1901 The protozoa. New York: MacMillan and Company. 



Cameron, F. 1910 Introduction to the study of the soil solution. Jour. Phys. 

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Cauda, A. and Sangioro, G. 1914 Untersuchungen iiber die Mikrofauna der 

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