^o 



SOIL BACTERIOLOGY 



6. Under favorable conditions nodules will begin to form 

 in ten to fifteen days. 



Fig. 6. — Showing inoculated alfalfa plant. 



7. Keep the cultures in a warm place — greenhouse or 

 near a window. 



8. After four and six weeks examine carefully for nodules, 

 noting the number, size, shape, and location. 



