CONTROL AND STIMULATION OF SOIL BACTERIA I29 
noticed, this commercial product, supposed to contain the bac- 
teria-producing root tubercles, was found to be a failure, although 
claims are still made of the success attending the use of the 
New Nitragin and of some of the other cultures of similar organ- 
isms. While these are often practical and while it would seem 
as if this method would be likely, in the future, to become success- 
ful, at the present time the results are somewhat uncertain. 
Inoculations with legume earth have given more nearly uniform 
success, and whenever it is desired to cultivate a legume in a 
soil where it does not readily grow, this inoculative method may 
be tried with good hopes of success. Soil from some locality 
where the legume grows luxuriantly should be imported and mixed 
with the field which is to be planted with the legume. But one 
should be careful that the inoculating soil does not bring trouble- 
some weeds or plant diseases. In using either the earth inocula- 
tions or pure cultures, ii must be borne in mind that if a soil is 
already well stocked with the tubercle bacteria, inoculations are 
not likely to do any good; but in soils where a new legume is to 
be grown or where the legume to be planted does not flourish, 
soil inoculation may be of decided advantage. 
Soil Inoculation with Manure.—Manure is added to the soil 
primarily as a means of furnishing plant food; but it has become 
evident that the inoculation of the soil with the immense amount 
of bacteria in the manure is in itself of extreme value, sometimes, 
as in pasture soil, of more value than the actual food substances 
in the manure. The use of manure upon the soil must, there- 
fore, be looked upon as one of the very useful methods of inocu- 
lating the soil with the bacteria needed to carry out the soil 
transformations. 
CONTROL AND STIMULATION OF SOIL BACTERIA 
Tt has become more and more evident, as information has accu- 
mulated, that a vigorous activity of the bacteria found in the 
soil is needed to carry out the various transformations of plant 
9 
