IO2 rvEQI.AIT.nifG LOST NITROGEN. 
probable that there could be in the soil a different variety of bacteria 
for every variety of legume, but rather that one kind of bacteria can 
grow in many legumes. But the facts are not quite so simple as this. 
Not all species of legumes are capable of developing root tubercles 
equally well in all soils. Some soils will luxuriantly support certain 
species of beans, peas, or clovers, producing a large crop, developing 
quantities of tubercles and fixing an abundance of nitrogen, while 
the same soil will not support other species of legumes with equal 
readiness. For example, the soil of Connecticut is not adapted 
to the legume called the soy bean. When this bean is planted in the 
ordinary Connecticut soil it does not flourish, but yields a small 
crop unless heavily fertilized, and does not produce tubercles. 
This species does, however, grow readily in Massachusetts. Some 
years ago the experiment was tried of importing Massachusetts 
soil, upon which this plant had produced abundant tubercles, 
and mixing it with the Connecticut soil, subsequently planting the 
soy bean. The result was an excellent growth of the soy bean 
and the development of tubercles. Afterward these particular 
plots of land were capable of producing large luxuriant crops of 
the soy bean, with abundant root tubercles and a large fixation 
of atmospheric nitrogen. Evidently Connecticut soil does not 
contain the bacteria adapted for producing the tubercles in the soy 
bean, although those which produce tubercles on the pea and the 
clover are abundant enough. 
Similar experiments have been repeated elsewhere until it has 
become evident that the root tubercle bacteria are not all alike. 
Varieties adapted to one species of legume may be unable to produce 
tubercles upon a second species; in some cases one type of bacteria 
may be able to grow in the roots of several allied legumes but not 
in others. For example, the tubercle organism of sweet clover 
will do well with alfalfa. All of these facts have suggested that 
there are different types of leguminous bacteria, each adapted to 
different species of legumes. 
To what extent this conclusion is true it is by no means easy to 
determine. It is certainly true that some varieties of legume will 
grow in soils with an abundant production of tubercles, while 
