Agricultural Chemistry. 
417 
wards to quote, but the unscrupulous unfairness of an anony- 
mous article in the Journal of the Highland Society will be fully 
apparent. W e have already shown how distinctly, in the Pre- 
face to his third edition, Baron Liebig admitted a change and 
perfecting in his views since the first. And yet, incredible as it 
inay^appear, our Northern critic admittedly makes bis quotations 
by Avhicli to fasten the accusation of misrepresentation upon our- 
selves, from Baron Lieblg's first edition, and from his ' Prin- 
ciples,' lately published in the course of the controversy ! 
One of the quotations made by this critic, with a view of 
showing that we have misrepresented Baron Liebig, in attributing 
to him an inadequate appreciation of the importance of avail- 
able nitrogen within the soil itself for the growth of some of our 
most important crops in agricultural quantity, he takes from the 
first edition, as given below. We give by its side the sentence 
as it occurs in Baron Liebig's third and fourth editions ; and 
the capitals are our own, to draw attention to the words altered 
from the earlier edition to the later ones. 
" Cultivated plants receive the " Cultivated plants receive the 
same quantity of nitrogen from the same quantity of nitrogen from the 
atmosjihere as trees, shrubs, and other atmosphere as trees, shrubs, and other 
wild plants ; but this is not suffi- wild plants ; and this is quite suffi- 
cient FOH the purposes OF AGRICUL- CIENT FOR THE PURPOSES OF AGRICUL- 
TURE." — 1st Edition, p. 85. ture." — Zrdai^d Aith Editions, p. 54. 
Notwithstanding, then, that in his third and fourth editions, 
Baron Liebig exactly reverses the opinion held in his first, on 
the very point in reference to which the sentence is brought 
against us — yet it is from the first edition that our critic quotes ! 
In this slight alteration, too, we have a key to the fundamental 
change in Baron Liebig's views in regard to the capability of a 
liberal supply of the constituents proper to the soil itself — the 
mineral constituents — to enable plants to obtain from the atmo- 
sphere " sufficient " nitrogen for an agricultural amount of crop. 
We shall now assume that we have given evidence enough of 
a change in Baron Liebig's views from his first edition to his 
later ones, to show that it is quite inadmissible to quote from bis 
earlier in judgment of our representations of his later opinions. 
The following is the manner in which we have ourselves repre- 
sented those opinions in reference to the point referred to by the 
critic in the ' Highland Society's Journal ' and also by a writer in 
the ' Saturday Review ' of November 10, 1855, et seq. : — 
" Practical agriculture consists in the artificial accumulation of certain 
constituents to he employed either as food for man or other animals, vj>on a space 
of ground incapable of supjportiiig them in its natural state. This definition 
of agriculture is, I think, important, as distinguishing English agriculture at 
least, from the system pursued in various parts of the world, where the popu- 
lation is small and the land of little value, viz., of taking only the natural pro- 
