Nitrogen Fixation 5 
used for irrigation the same; the cultivation in both cases was ex¬ 
cellent; the men were not new hands at growing melons, the only 
difference was that the one patch was on a piece of recently broken 
alfalfa ground and the other on ground that had been cropped for 
several years. There were no features of either soil which would 
suggest to anyone not conversant with certain facts, that there was 
any difference in these fields suggestive of any explanation for the 
difference in the growth of the plants. It was only after having 
these certain facts forced on my attention for years that they really 
became suggestive to me. 
The brown lines along the edge of the irrigation furrow might 
mean heavy fertilization with barnyard manure; it might be due 
to other perfectly harmless if not beneficient causes, but in these 
cases they are probably significant of the causes producing the dif¬ 
ference in the growth of these young plants. We do not hope in 
the present bulletin to succeed in tracing out general relations, this 
is a work for the future concerning which we only promise that it 
will be prosecuted diligently, with the care and conservatism that 
its importance demands. It is proper that we should meet the ques¬ 
tions presenting themselves in our agricultural practices with only 
one view, to find out the facts as they obtain at the time 
without predicting results; though they seem to be already certain 
and only lack verification. For these reasons no attempt or but 
little attempt, will be made to more than set forth some facts which 
have been established, reserving much detail work and the extension 
of this work in bacteriological lines for the future. Work of this 
kind is already in progress and some results have been attained, 
but the work is not ready for publication. 
No one can foresee what the problem of the fixation of an ex¬ 
cessive amount of nitrogen in our soils may develop into, whether 
it means the introduction of a new practice or a serious difficulty 
which we may not be able to control. It may for a while present 
difficulties because we know but little about such a thing. But if 
it should prove to be a permanent condition in our soils I am cer¬ 
tain that we shall be able to find some remedy perhaps not immedi¬ 
ately, but quickly. 
Fortunately the trouble expressed itself locally with great vio¬ 
lence during May and June of 1909. By fortunately it is not 
meant that it was a good thing that certain persons suffered loss 
but simply that the loss was so severe that the people of whole 
neighborhoods have seen with their own eyes, that something is 
very seriously wrong, for the sudden death of a large portion of an 
orchard is convincing proof of this. At this time the foliage of 
many trees, apple trees mostly, showed a burning, beginning at the 
apices of the leaves, extending rapidly along the margins until the 
