268 BULLETIN OF THE BUSSEY INSTITUTION. 
doctrine, but also of a just appreciation of the significance of the so- 
called inert soil-nitrogen.* Much light has indeed been thrown upon 
the subject indirectly by experiments upon the formation of nitrates 
in the soil, as will be mentioned hereafter. But it would almost seem 
as if the not unnatural anxiety of chemists to detect and explain the 
conditions and circumstances under which the nitrogen of dead vege- 
table or animal matters may be changed into nitrates or ammonium 
salts had distracted the attention of many of them from the funda- 
mental fact that under certain conditions the nitrogen of vegetable 
mould is, in part at least, available for the support of growing plants. 
It is the purpose of the present paper to uphold this cardinal fact, 
and to urge that in the existing condition of agricultural knowledge it 
is equally important that the fact itself should be recognized and in- 
sisted upon, and the general conditions which influence or control it 
observed, as that the precise manner or form in which the nitrogen 
natural to the soil gets into the plant should be studied. It has been 
unfortunate that many chemists in their haste to discard certain erro- 
neous views with which the subject was at one time encumbered, have 
well-nigh lost sight of several facts that were greatly insisted upon by 
some of the earlier chemists and by not a few agricultural writers. It 
would be unprofitable in the present connection to consider the various 
theories and speculations that led to this result, or even to dwell upon 
the old facts which the theories obscured; since there is no lack either 
of experimental proof with which to illustrate the present argument, or 
of examples that may be drawn from modern field practice. No mat- 
ter how our knowledge of the truth that the soil-nitrogen may be used 
by plants has been acquired, it is manifest that the simple fact has a 
certain practical value which may be discussed as a subject by itself and 
upon its own merits, quite independently of any historical interest, or 
of the scientific question whether the nitrogen is first changed to a 
nitrate before the roots can absorb it, or whether it enters their pores 
in some form that is at present wholly unknown to us. 
* Mulder (in his “ Chemie der Ackerkrume,” 2 pp. 153-183) has given an 
excelient summary of what was known about the nitrogen of the soil at the 
time whien his book was written; but, as he wrote under the conviction that the 
soil contained much ammonia, the general tone of his discussion of the subject, 
and some of his conclusions, are very different from what they undoubtedly 
would have been if the real insignificance of the ammonia in the soil had been 
fully recognized. 
