254 AGKICULTURAL AND INDUSTRIAL BACTERIOLOGY 



of stimulating the meristematic cells to increased rapidity 

 of development. In consequence a small tumor or mass of 



FIG. 58. NODULES ON ROOTS OF A LEGUMINOUS PLANT. 



cells develops rapidly and protrudes from the main portion 

 of the root as a nodule. This nodule may be regarded as a 

 modified rootlet. 



