WORK OF BACTERIA 
5i 
were unable to use free atmospheric nitrogen and 
must obtain it directly from the soil in a highly or¬ 
ganized form, the importance of the problem increased 
greatly, and the gravest consequences were predicted 
by those familiar with the rapidity with which this 
valuable element was being wasted.”—Farmers’ Bulle¬ 
tin No. 214, Beneficial Bacteria for Leguminous 
Crops. 
Nitrogen in combination available for plant food is 
wasted in many ways. Food and other organic wastes, 
as sewage, are burned or run into the sea instead of 
being returned to the earth, which is the natural place 
of disposal. 
There are natural sources of stored nitrogen in 
saltpeter beds and guano deposits, but these are rapidly 
disappearing. Even if they were sufficient in quantity 
they are not everywhere present and therefore must 
be expensive. Their aid would not be available for all. 
The bacteria are more generally present and ready 
to work. Although unknown and therefore uncred¬ 
ited, they have been working during all the ages since 
vegetation appeared, not only by their general agency 
in producing fertility of the soil through the products 
of decomposition, but also in certain plants through 
their ability to take from the air its free nitrogen. 
From the earliest days of agriculture it has been 
recognized that all plants belonging to the leguminosae 
have a decidedly beneficial effect upon the soil. Pliny 
wrote: “The bean ranks first among the legumes. 
fraste of 
iTitrogen 
Nitrifying 
Bacteria 
