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legumes, the results are somewhat indefinite, and it is diffi- 
cult at present to determine the truth. Be this as it may, the fact 
still remains that it is to legumes chiefly that we must look for the 
restocking of our soils with nitrogen. 
It has been a difficult matter to make any very valuable quan- 
titative tests upon this power of bacteria and legumes to assimi- 
late nitrogen from the air. Still, within the last year or two quite 
a number of extended experiments have been turned in this direc- 
tion. Experiments have shown in the first place, that in regard to 
some of the legumes at least, a greater amount of nitrogen can be 
assimilated through the agency of the bacteria alone than can be 
assimilated by the same plants if they are fed with nitrogen foods. 
The same species of legumes are grown under two conditions, in 
both cases supplied with the organism which produces its root 
tubercles, and in the one experiment fed with nitrogen foods in 
the form of nitrates, and in the other not thus fed. The result 
shows a considerable difference to the advantage of the plants that 
are not fed with nitrates. The amount of nitrogen which can be 
assimilated and fixed in the soil by these legumes is really very 
great. In experiments with scarlet clover it has been found that a 
plant will assimilate from the air more than twelve times the amount 
of nitrogen in the seed. In one of the most recent experiments it 
has been found that by the use of beans a single crop assimilates 
and fixes in the soil 225 pounds of nitrogen per acre, equivalent 
to about 1400 pounds of nitrate of soda. These figures are very 
striking and suggestive, and they show plainly what a very great 
agent in the fixation of nitrogen the legume plants can become 
when properly associated with their appropriate species of bacteria. 
Peas, beans, cow peas, alfalfa, vetch and clover appear thus far to 
be the most valuable plants for this purpose, but other legumes 
serve the same purpose. 
These experiments promise to be of the most incalulable 
value to the agriculturist and to the agricltural interests of the 
world in the future. They offer to our farmers a means of get- 
ting nitrogen without going to the expense of buying it, of enrich- 
ing their soil by simply cultivating upon it plants which experi- 
ment has shown most appropriate to the soils in question. They 
emphasize the value of clover as a crop to precede wheat, and ex- 
