BACTERIA OF OLD SOILS 103 



ments carried out in France, Germany, and the United States, 

 it was observed that Azotobacler activity and nitrogen fixation 

 were somewhat less in summer than in spring and fall. Clostri- 

 dium pastorianurn}^ has been found to be more resistant than 

 Azotobacter, for it may exist for at least seven years in a dry 

 condition. 



Owing to the commercial methods of preparing and shipping 

 inoculating material of Bacillus radicicola for seed or soil, the 

 resistant powers of this organism toward desiccation have been 

 thoroughly investigated. Harding'' and Prucha report that the 

 method of drying cultures of B. radicicola on cotton is inherently 

 unsatisfactory because of the inability of that organism to per- 

 sist on dry cotton. Chester'^ corroborates the above cited re- 

 sults, finding however, that extremely virulent strains can suc- 

 cessfully be dried on cotton provided the drying process be rapid, 

 the culture immediately sealed and used shortly thereafter. Never- 

 theless, Lohnis'^ finds that B. radicicola can resist long enduring 

 droughts in soils without serious effect, especially in \'iew of 

 Simons''^ investigation determining that micro-organisms are far 

 more resistant when in the soil than on most other media. Yeast 

 cells'^ appear more resistant than B. radicicola. ' 



The researches of Schlosing'^ and Muntz decisively demonstrate 

 that the organisms involved in the process of nitrification offered 

 little resistance toward drying. Winogradsky" found that nitro- 

 bacteria in zoogloea form were seriously interfered with if dried 

 twenty-four hours, while Wimmer'* determined that in soils the 

 effect was far less marked. Somewhat in contrast to the findings 

 of Rahn on ammonification, Lemmermann,'^ Fischer, Kappen 



'« Handb. der Teck. Myk. 3:6. 

 " New York Exp. Sta. Bui. 270. 



Delaware Exp. Sta. Bui. 78. 



Einfuhrung in die Bakteriologie, p. 670. 

 " Jahresber. der Ver. f. angew. Botanik 5: 154. 1907. 



Microbiology, p. 151. 



Citation — Einfuhrung in die Bakteriologie, p. 617. 

 " Citation — Einfuhrung in die Bakteriologie, p. 617. 

 '8 Zeitschr. f. Hyg. 48; 170-174. 

 " Landw. Yahrb. 38: 344-345. 1909. 



