BACTERIA IN THE INDUSTRIES. 



95 



FIG. 44. Longitudinal section through red clover rootlet, showing tubercle formation 

 due to the root nodule microbe, Rhizobium mutabile. The tubercle is only partially de- 

 veloped, a, root hairs. These do not develop on the nodule, b, the normal root par- 

 enchyma, c, vascular tissue, d, infected area, also showing the infecting strands (In- 

 fectionsfaden). The cells are filled with bacteria, e, apical areas, the growing areas of 

 the tubercle. 



