SECTION III., 1900. [58] Trans. R. S. C. 
V.—Canadian Experiments with Nitragin for Promoting the Growth 
of Legumes. 
By Frank T. Saurt, M.A., F.C.S., F.LC., 
AND 
A. T. CHARRON, B.A, 
(Read May 29th, 1900.) 
In 1886, Hellriegel and his colleague, Wilfarth, having brought to a 
suceessful issue their investigation on the sources of nitrogen available 
to farm crops, demonstrated that the free, 7.e., the uncombined, nitrogen 
of the atmosphere can be utilized by the legumes. This, they announced, 
was effected through the agency of certain micro-organisms or bacteria 
present in the soil, and which, attaching themselves to the roots and 
rootlets of the legumes, caused to be formed thereon nodules or tubercles. 
The bacteria occupying these nodules, they showed, have the power of 
absorbing free nitrogen from the air present in the interstices between 
the soil particles, converting it into certain nitrogenous compounds which 
are subsequently received into the circulation of the host plant and 
finally stored up in the tissue of root, stem and leaf. 
This discovery satisfactorily set at rest a question that had received 
the attention of the foremost agricultural chemists of the day, and re- 
specting which there had been much controversy between those working 
in England and on the continent. It had been long noticed that the 
cereal and root crops consumed the soil nitrogen, their growth conse- 
quently necessitating the continued application of nitrogenous manures, 
while, on the other hand, the legumes not only flourished without such 
food, but evidently left the land actually richer in nitrogen than it had 
been previously. It was further acknowledged that this additional and 
stored-up nitrogen was available for subsequent crops. But until Hell- 
riegel’s announcement, no convincing explanation of these facts had been 
advanced, there had been no scientific basis for the practice of introduc- 
ing clover (a prominent member of the leguminosæ) in a rotation. 
As far as we know at present, the leguminose only can make this 
use of atmospheric nitrogen ; for all other plants this essential element of 
their food must be drawn from the humus compounds of the soil, first 
being converted into nitrates. If productiveness is to be maintained, 
nitrogen in some form must be returned to the soil, for cropping with 
plants other than the legumes necessarily reduces the soil’s store of this 
element. We find in these statements the reason for the classification 
recently advanced, viz., of nitrogen-collectors and nitrogen-consumers— 
