23 
able to assimilate by the help of the bacilli, so that the two are 
mutually helpful, instead of the one being destructive to the other, 
as in the case of ordinary parasites. In consequence of this pecu- 
liar property of the leguminose, crops of this order of plants can - 
be grown without any nitrogenous manures; and, as I mentioned 
before, nitrogenous manures are very expensive. Experiments are 
being made in the United States as to whether it is possible to get 
the bacilli of a leguminous plant to live on the juices of one of the 
grain-bearing plants such as wheat; so that the latter might be 
able to make use of the free atmospheric N. The plants selected 
were the white melilot (Melilotus albe) closely similar to the 
bokhara clover as the leguminous, and maize as the graminaceous 
plant. The steps of the investization have been to make a suitable 
medium in which the bacilli of the melilot nodules would thrive; to 
gradually change this medium for a leguminous to a graminaceous 
nature; at the same time to modify the bacilli by successively 
transferring them from a highly leguminous medium to a highly 
and eventually an exclusively graminaceous medium, and finally to 
inoculate graminaceous plants with the modified bacilli. The 
leguminous plants eventually used were two, the white melilot and 
the bean, ani the graminaceous plants were maize and oats. A 
considerable time must elapse before the investigation is completed, 
but so far the indications are that the bacilli of leguminous plants 
are capable of being sufficiently modified to develope to a certain 
extent in the root cells of maize; on the other hand, no visible 
effect has yet been produced in the case of oats. Investigations of 
this character cannot be unduly hurried, and much work has yet to 
done in completing the details of the discoveries already made. It 
is desirable to learn for example the exact vole of the bacilli and 
what course of changes the free N. of the air undergoes in its migra- 
tion into the plants. Questions such as these will no doubt be 
answered in time, and the near future promises to be fruitful in the 
solution of problems which must have a profound bearing upon the 
development of economic agriculture. 
To recapitulate briefly: Plants of the natural order Leguminose 
have little nodules in their roots. These nodules contain colonies 
of bacilli. These bacilli live on the juices of the plant, and at the 
Same time have some effect on the N. of the air which exists in the 
soil, so that the nodules contain an unduly large proportion of N. 
- This storage of N. is made use of by the plant in its developement. 
Thus leguminous plants can obtain the N. they require for growth 
in soils in which nitrates are deficient, so that other crops would 
require costly nitrogenous manures. The roots of these leguminous 
plants, being left in the soil, make the soil richly nitrogenous for 
the next crop. A problem now waiting solution is this—Can 
wheat, oats, barley, and maize be supplied with a bacillus which 
