arises whether B. radicola, the bacteria of the legume tubercles, can fix atmospheric nitrogen independently of its life in the legume tubercles. As a matter of fact, Beyerink and Mazè claim to have proved that this organism can fix elementary nitrogen independently of legumes. We should note here the remarkable fact that although this organism is so universally distributed and common in all soils, all attempts to isolate it from the soil directly have not been successful.
There are probably a half a dozen bacteria capable of fixing atmospheric nitrogen known to-day, and there is little doubt that others will be found before long. As it is, we are fully justified in the claim that soil bacteria are a potent, nay, an indispensable, factor in the creation of the world's food. Though they are to most of us an invisible world, though many of us never suspect their existence, they are yet our staunch friends, living their brief life, contributing to a broader life, making it possible for the finite to dream of the infinite.