decay of animals a chief sustainer of the life of 
plants, to run a continual circle of connecting 
agency through non-organic matter, vegetables, 
and animals, and, in general, to act so prominent 
and constant a part in the grand reciprocities of 
the vegetable and the animal worlds as to be the 
chief of the chemical elements which demand the 
thorough study of every well-informed cultivator 
of the soil. Though the mode in which it acts 
is still, except in a few instances, obscurely 
known, yet the facts of its acting are exceedingly 
obvious and far beyond controversy ; and these 
facts give azote its main interest to even a scien- 
tific chemist. Its serving as a diluent of oxygen 
and as a vast storehouse receptacle for this and 
other gases—or its being a gas at all and so large 
an element of the atmosphere—are unquestion- 
ably circumstances of great value in themselves, 
and also show how, under the will of the infin- 
itely wise Creator, a grand physical agent, made 
to serve an ulterior purpose, may at the same 
time equally serve a subordinate one; yet they 
must be strictly regarded as mere accessory cir- 
| cumstances, and not confounded with the main 
designs and uses of the gas. “ After oxygen,” 
remarks Liebig, “ few substances are of more im- 
| portance in the economy of nature than nitro- 
gen. Forming so great a part of our atmosphere, 
it is scarcely possible to conceive that it must 
not be subservient to other important purposes, 
besides that of merely diluting oxygen gas. It 
is dissolved in the water of the sea, of lakes, 
springs, and rivers. It enters largely into the 
composition of some vegetables, and of all ani- 
mals; and it is extremely probable that great 
phenomena, now obscured, such as the renova- 
tion of the air, rain, and perspiration, would be 
‘| solved by an accurate knowledge of this gas.” 
Compound chemical elements containing azote 
are technically said to be nitrogenous, azotated, 
or azotized; and the chief of these found in ani- 
mals and plants are gelatine, albumen, gluten, 
caseum, legumine, urea, osmazome, and fibrin. 
All plants imbibe or absorb and fix azote; yet, 
when viewed in the aggregate, they contain so 
very small a proportion of it compared to their 
other elements, that, till a few years ago, it was, 
in many instances, unobserved or unheeded in 
their analysis, Animals, on the other hand, pos- 
sess so large a proportion of it in their. blood, in 
their juices, in their organisms, and generally 
throughout their system, that its presence is the 
cause of many of their most characteristic chemi- 
cal features. All the higher orders of animals 
receive their nourishment directly or indirectly 
from vegetables; they obtain the characteristics 
of that nourishment, or the constituents of blood, 
in the form of nitrogenous elements; for each 
pound of nitrogen which they require in order 
to the sustenance of life and the maintenance of 
health, they must consume as much vegetable 
matter in the form of food as contains a pound 
of nitrogen ; and as both the proportion of nitro- 
AZOTE. 
303 
gen in each healthy animal and the quantity of 
it in each edible vegetable is fixed or uniform, an 
exact correlation exists between the nourishment 
of any animal, and the nitrogenous contents of 
each kind of vegetable aliment. Yet as both 
animals and vegetables are composed of several 
proximate principles or compound elements, and 
as these principles exceedingly differ from one 
another in their nitrogenous character, some, as 
the fat of animals and the woody fibre of plants, 
being wholly destitute of nitrogen, while others, 
as albumen and gluten, contain it in great quan- 
tities, so animals may increase in nitrogenous 
elements to the neglect of non-nitrogenous ones, 
or may increase in non-nitrogenous elements to 
the neglect of nitrogenous ones, according to the 
nature of their food. Fatty matter, for example, 
requires for its formation an excess of hydrogen, 
but neither contains nor requires any nitrogen ; 
while muscle requires no excess of hydrogen, but 
consists almost wholly of the nitrogenous ele- 
ments, albumen, fibrin, and osmazome, and, in 
consequence, requires a high excess of nitrogen. 
If, therefore, cattle are fed upon substances which 
contain a small proportion of nitrogen and an ex- 
cess of hydrogen, such as oil cake, they speedily 
become fat, without acquiring a proportional in- 
crease of beef or muscle ; and if, on the contrary, 
they are fed on substances which are rich in 
nitrogen, such as the seeds of leguminous plants 
and of the cereal grasses,—especially when they, 
at the same time, enjoy the powerful excitant to 
the increase of muscle which is afforded by steady 
and habitual muscular exertion,—they speedily 
become fuller and rounder in their masses of 
muscular tissue, without acquiring any propor- 
tional increase of fat. An obvious inference is, 
that to feed an animal with the view of fattening 
him, and to feed him with the view of strength- 
ening him, are totally different processes, and re- 
quire totally different aliments; and another in- 
ference, though not so obvious an one, is, that 
neither of these processes can be much or long 
continued to the exclusion of the other, without 
causing very serious damage to the constitution. | 
As the proportion of azote is always greater in 
animals than in vegetables, so the more of azote 
any vegetable contains, the less of that vegetable 
is required for the nourishment of any animal; 
and the less of azote another vegetable contains, | 
the more of this vegetable is required for the 
animal’s nourishment. This principle is of the 
highest moment in all the economics of a farm, 
and indeed of human life and the world’s affairs ; 
and it has been worked out and vindicated by an 
energy and a bulk of experimental proof which 
must force conviction on even the dullest thinker. 
A number of experiments were instituted, a few 
years ago, by various individuals on the conti- 
nent, with the view of ascertaining the nutritive 
powers of various kinds of food, and were per- 
formed both with mechanical care as to the quan- 
tities of the food employed, and with chemical. 
Sa SS ae 
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