Agricultural Chemistry. 
421 
as practised in Great Britain, on which Baron Liebig has 
addressed the English public in his various writings, we say : — 
That the title of one of his publications is — ' Organic 
Chemistry in its Applications to Agriculture and Physiology.' 
That of another is — ' An Address to the Agriculturists of 
Great Britain, on the Principles of Artificial Manuring.' 
And of another — ' On Artificial Manures.' 
That in the preface to the third and fourth editions of his 
main work, he states them to be put forth, after having endea- 
voured to make himself " acquainted with the condition of 
practical farming, and with what it requires, by a journey 
through the agricultural districts of England and Scotland." 
We were justified then in concluding that Baron Liebig put 
forth his doctrines not only as applicable to normal vegetation, 
but to agriculture and to the existing condition and wants of 
agriculture as practised in Great Britain. We will now show, 
by quotations from his works, whether we have mis-stated his 
views on the following important points, viz. : — 
The dependence of our cultivated plants, whether graminaceous 
or leguminous, upon atmospheric sources for their supply of 
nitrogen. 
The direct dependence of the amount of produce on the available 
mineral food of plants within the soil. 
The nature of the restitution to be made from without in a 
course of practical agriculture. 
He says (4th edition, as already quoted) — 
" Cultivated plants receive the same quantity of nitrogen from the atmos- 
phere as trees, shrubs, and other wild plants ; and this is quite sufficient for 
the purposes of agriculture." — p. 54. 
" It is obvious, therefore, that there is no deficiency of atmospheric food for 
the plants of these regions, and there can he none for our own cultivated 
plants." — p. 167. 
" Are the fields of Virginia, the fields of Hungary, our own cultivated plants, 
not able to receive it from the same sources as the wild-growing vegeta- 
tion? Is the supply of nitrogen in animal excrements a matter of absolute 
indifference f or do we obtain in our fields a quantity of the cok- 
STITUENTS OF THE BLOOD, ACTUALLY CORRESPONDING TO THE SUPPLY OF 
AMMONIA ? " — p. 205. The capitals are Baron Liebig's own. 
"Hence it is quite certain, that in our fields, the amount of nitrogen in the 
crops is not at all in proportion to the quantity supplied in the manure, and 
that the soil cannot be exhausted by the exportation of products containing 
nitrogen, (unless these products contain at the same time a large amount of 
mineral ingredients), because the nitrogen of vegetation is furnished hy the atmo- 
sphere, and not by the soil." — p. 210. 
" Is fertility not quite independent of the ammonia conveyed to the soil? 
If we evaporated urine, dried and burned the solid excrements, and supplied 
to our land the salts of the urine, and the ashes of the solid excrements, would 
not the cultivated ])lants grown on it — the gramine<x and leguminosce — obtain 
their carbon and nitrogen from the scnne sources whence they are obtained by 
the gramiuca) and leguminosro of our meadows There can scarcely he a 
