230 
ON THE NITROGEN OF PLANTS. 
ART. L. — SOURCE AND ASSIMILATION OF THE NITROGEN 
OF PLANTS. 
Extracted from Liebig's Organic Chemistry of Agriculture and Physiology. 
u We cannot suppose that a plant would attain maturity, 
even in the richest vegetable mould, without the presence of 
matter containing nitrogen; since we know that nitrogen 
exists in every part of the vegetable structure. The first 
and most important question to be solved, therefore, is : 
How and in what form does nature furnish nitrogen to vege- 
table albumen, and gluten, to fruits and seed ? 
This question is susceptible, of a very simple solution. 
Plants, as we know, grow perfectly well in pure charcoal, 
if supplied at the same time with rain-water. Rain-water 
can contain nitrogen only in two forms, either as dissolved 
atmospheric air, or as ammonia. Now, the nitrogen of the 
air cannot be made to enter into combination with any ele- 
ment except oxygen, even by employment of the most power- 
ful chemical means. We have not the slightest reason for 
believing that the nitrogen of the atmosphere takes part in 
the processes of assimilation of plants and animals ; on the 
contrary, we know that many plants emit the nitrogen, 
which is absorbed by their roots, either in the gaseous form, 
or in solution in water. But there are, on the other hand, 
numerous facts, showing, that the formation in plants of sub- 
stances containing nitrogen, such as gluten, takes place in 
proportion to the quantity of this element which is conveyed 
to their roots, in the state of ammonia, derived from the pu- 
trefaction of animal matter. 
Ammonia, too, is capable of undergoing such a multitude 
of transformations, when in contact with other bodies, that in 
this respect it is not inferior to water, which possesses the 
