128 SOME PRACTICAL LESSONS FROM SOIL BACTERIOLOGY 
existing in our knowledge of soil bacteriology. But in spite of it 
all, some definite conclusion as well as practical lessons can 
already be drawn.* 
SOIL INOCULATIONS 
The need of bacterial action in the soil naturally suggests the 
question whether the necessary activities may not be brought 
about or increased by inoculating the soil with the desired bac- 
teria, just as a brewer inoculates his malt with yeasts. This plan 
has been tried extensively by at least two different methods. 
Nitrogen Fixers, Alinit, Nitrifying Bacteria—Alinit is a 
material placed on the market and widely used for a time. It 
was said to be made from a pure culture of the bacteria that can 
fix free nitrogen in the soil. Careful testing, however, failed to 
show any favorable results from the use of alinit, and so it has 
been abandoned. Other nitrogen fixers have also been tested 
as pure cultures inoculated into soil, with like failure. The 
attempt to simulate nitrification by the use of cultures of nitrifiers 
has likewise failed. 
Tubercle Bacteria of Legumes.—Nitragin—As already 
* Reference should be made here to the conception concerning soil fertility held 
by some, notably those connected with the Bureau of Soils of the Department of 
Agriculture, that the primary trouble in “worn-out soils” is not lack of sufficient 
plant food, but the presence of poisonous excretions that prevent the growth of 
plants. It is claimed that each crop excretes into the soil certain substances that 
serve as poisons to another similar crop on the same soil. It is said that practically 
all soils at all times contain a sufficiency of food, but that the accumulation of these 
excretions after a time renders the soil incapable of supporting a satisfactory crop. 
The value of fertilizers is not to give food, but to neutralize these excretions, and 
that a proper rotation of crops will serve just as well, since the excretions from one 
kind of plani, while injurious to the same plant, will not injure a different kind of 
plant. Such a conception would largely revolutionize the methods of treating the 
soil, since, if accepted, it would lead to the abandonment of any attempt to feed the 
crops and would replace such methods by those designed simply to remove the 
poisonous excretions. This theory as to soil fertility would bring into greater 
prominence the agencies of soil bacteria, but it is very vigorously disputed and is 
not very widely accepted. 
