56 ROYAL SOCIETY OF CANADA 
the former consisting of the legumes only ; the latter comprising all 
other crops. By the use of leguminous crops it is evident, therefore, that 
there is a ready way in which we can continually enrich the soil with the 
costliest of all the constituents of plant food—a way at once the most 
economical and profitable, and one that appropriates this valuable element 
(nitrogen) from a supply otherwise valueless to agriculture. This dis- 
covery, therefore, was not simply of scientific interest, but one of great 
value and importance to agriculture, and, therefore, indirectly to the 
whole community. 
In the practical application of this method of soil enrichment by the 
legumes, there are two facts which must be taken into consideration, 
The first is: that without the aid of these special bacteria, clover, pease, 
beans, and all other legumes, must obtain their nitrogen from the soil, as 
do other plants; the second is: that though apparently very widely 
distributed, these bacteria are not present in all soils. To overcome this 
latter difficulty, in other words, to induce a vigorous growth of a legume 
and secure the entrapping of nitrogen in soils destitute of these micro- 
organisms, Dr. Nobbe, of Tharand, Saxony, proposed soil inoculation. This 
he effected by obtaining soil from a field in which the roots of the legume 
growing thereon possessed an abundance of nodules, and which was conse- 
quently rich in the special bacteria, and sowing it on the land to be impreg- 
nated. This plan, though somewhat cumbersome and in some cases rather 
costly, proved eminently successful. To further simplify the problem and 
extend the application of this discovery, Dr. Nobbe next preyared, by 
methods well-known to bacteriologists, cultures or preparations of these 
bacteria direct from the nodules. These cultures have been made by the 
well-known house of Meister, Lucius & Brüning, Hoechst am Main, Ger- 
many, and have been for sale for some years past under the name of Witra- 
gin, sufficient to inoculate an acre being sold for about $1.25. Subsequent 
work seemed to show that each legume had its own particular organism, 
those for clover, for instance, not influencing the growth of vetches, and 
vice versa. This led to the preparation of many Nitragins, and as many 
as 17, specially intended for the different members of the order leguminosæ 
have been for sale—to be used according to the crop to be sown. 
Nitragin has been used in two ways: by inoculating the soil and by 
inoculating the seed. The “culture” is diluted with sufficient cold or 
lukewarm water, and in the first case used to moisten a quantity of soil, 
which, after being allowed to dry, is spread evenly over the field and 
deeply harrowed in. In the second method the diluted Nitragin is 
sprinkled over the seed, which is then partially dried by being mixed 
with dry sand or loam and at once sown. 
Our first series of experiments with Nitragin at the Experimental 
Farm, Ottawa, was begun in the spring of 1897, using the preparations for 
clover, horse beans, alfalfaor lucerne, and vetch. Both methods of inocu- 
