9 8 



PHARMACEUTICAL BACTERIOLOGY. 



FIG. 48. R. mutabile as it appears in mature nodules of red and white clover root 

 nodules. This may be considered the extreme form variation due to hyper-nutrition. 



FIG. 49. R. mutabile from the root nodules of Trifolium heterodon, showing the ex- 

 treme form variation due to hyper-growth. The forms shown in Figs. 7, 8 and 9 are 

 simply natural involution forms of the same species due to differences in environment and 

 host relationship. The chromatin bodies found in the hyper-nourished forms (Fig. 48) 

 are probably reserve products. 



