~ BACILLUS RADICICOLA FROM DIFFERENT LEGUMES 67 



5. Incubate under anaerobic conditions for seven to 

 ten days at 20° C, and make transfers from several well- 

 isolated colonies into tubes of Winogradsky's solution, 

 and incubate as before. If the cultures are not pure, 

 they should be replated. 



Exercise 34 

 ■ -/ 

 Isolation of Bacillus Radicifcola from Different Legumes 



I. Thoroughly wash the roots of several legumes {e. g., 

 red clover, alfalfa, sweet clover, vetch, and soy beans) 

 'under the tap. 



Fig. 4. — Plate colonies of Bacillus radicicola from clover, after ten days at 

 . ■ 28° C; X 2. 



2. Compare the number, size, and position of the nodules 

 on the roots of these different legumes. \ 



