258 
THE ROOT 
The relation which exists between the plants which profit 
by the work of the nitrogen-gathering bacteria and at the 
same time furnish them protection is an illustration of 
symbiosis (sym-bl-o'sis: Greek, sym, together; bios, life), 
Figure 247. — Effect of Bacteria on the Growth of Red Clover in a 
Poor Sand. 
Left, uninoculated; right, inoculated. 
the relation of mutual helpfulness between organisms of 
different kinds. 
223. Inoculation. — Nitrogen-gathering bacteria are likely 
to be present in all soils in small numbers, but in order to 
