Phenix Gazette

ANIMAL KINGDOM.
The various bodies around us, which form
the objects of chemical research, have all undergone a number of combinations and decompositions before we take them in hand for examination. These are all consequences of the
same attractions or specific properties that we
avail ourselves of, and are modified likewise by
virtue of the situations and temperatures of the
bodies presented to each other. In the great
mass of unorganised matter, the combinations
appear to be much more simple than such as
take place in the vessels of organised beings,
namely, plants and animals: in the former of
which there is not any peculiar structure of
tubes conveying various fluids; and in the latter
there is not only an elaborate system of vessels,
but likewise, for the most part, an augmentation
of temperature. From such causes as
these it is, that some of the substances afforded
by animal bodies are never found either in vegetables or minerals; and so likewise in vegetables are found certain products never unequivocally met with among minerals. Hence, among
the systematical arrangements used by the
chemists, the most general is that which divides
bodies into three kingdoms, the animal, the
vegetable, and the mineral.
Animal, as well as vegetable bodies, may be
considered as apparatus for carrying on a determinate series of chemical operations. Vegetables seem capable of operating with fluids
only, and at the temperature of the atmosphere.
But most animals have a provision for mechanically dividing solids by mastication, which answers the same purpose as grinding, pounding,
or levigation, does in our experiments; that is
to say, it enlarges the quantity of surface to be
acted upon by solvents. The process carried
on in the stomach appears to be of the same
kind as that which we distinguish by the name
of digestion; and the bowels, whatever other
uses they may serve, evidently form an apparatus for filtering off the more solid parts of the aliments,
which are probably of such a nature as not to
be rendered fluid, but by an alteration which
would perhaps destroy the texture of the machine itself, are rejected as useless. When this
filtering fluid passes into circulatory vessels,
through which it is driven with considerable
velocity by the mechanical action of the heart.
it is subjected, not only to all those changes
which the chemical action of its parts are capable of producing, but is likewise exposed to
the air of the atmosphere in the lungs, into
which that elastic fluid is admitted by the act
of respiration. Here it undergoes a change of
the same nature as happens to other combustible bodies when they combine with its vital
part or oxygen.
This vital part becomes condensed, and combines with the blood, at the same time that it gives out a large quantity of
heat, in consequence of its own capacity for
heat being diminished. A small portion of
azote likewise is absorbed, and carbonic acid is
given out. Some curious experiments of Spallanzani show that the lungs are not the sole organs by which these changes are effected.—
Worms, insects, shells of land, and sea animals,
egg shells, dead animals, even after they have
become putrid, are capable of absorbing oxygen from the air, and giving out carbonic acid.
They deprive atmospheric air of its oxygen as
fully and as completely as phosphorus. Shells,
however, lose this property when their organization is destroyed by age.—Amphibia, deprived of their lungs, live much longer in the open air, than others in air destitute of oxygen
It is remarkable, that a larva, weighing a few
grains, would consume almost as much oxygen
in a given time as one of the amphibia a thousand times its bulk. Fishes, alive and dead,
animals, and parts of animals, confined under
water in jars, absorb the oxygen of the atmospheric air over the water. Muscles, tendons,
bones, brain, fat and blood, all absorb oxygen
in different proportions, but the blood does not
absorb most; and bile appears not to absorb
any.
It would lead us too far from our purpose if
we were to attempt an explanation of the little
we know respecting the manner in which the
secretions or combinations that produce the various animal and vegetable substances are effected, or the uses of those substances in the economy of plants and animals. Most of them
are very different from any of the products of
the mineral kingdom. We shall, therefore, only add, that these organized beings are so contrived, that their existence continues, and all
their functions are performed, as long as the
vessels are supplied with food or vegetable materials to occupy the place of such as are carried on by evaporation from the surface, or otherwise, and as long as no great change is made,
either by violence or disease, in those vessels,
or the fluids they contain.— But as soon as the
entire process is interrupted in any very considerable degree, the chemical arrangements
become altered, the temperature in land animals is changed, the minute vessels are acted
on and destroyed, life ceases, and the admirable
structure, being no longer sufficiently perfect,
loses its figure, and returns, by new combinations and decompositions, to the general mass
of unorganised matter, with a rapidity which
is usually greater the more elaborate its construction
Animal and vegetable substances approach
each other by insensible gradations; so that
there is no simple product of the one which
may not be found in greater or less quantity in
the other. The most general distinctive character of animal substances is that of affording
volatile alkali by destructive distillation. Some
plants, however, afford it likewise. Neither
contain it ready formed; but it appears to be
produced by the combination of hydrogen and
azote, during the changes produced either by
fire, or by the putrefactive process.
When animal substances are left exposed to
the air, or immersed in water or other fluids,
they suffer a spontaneous change, which is
more or less rapid according to circumstances
The spontaneous change of organized bodies is
distinguished by the name of fermentation In
vegetable bodies there are distinct stages or
periods of this process, which have been divided
into the vinous, acetous, and putrefactive fermentation. Animal substances are susceptible
only of the two latter, during which, as in
all other spontaneous changes, the combinations of chemical principles become in general
more and more simple. There is no doubt but
much instruction might be obtained from accurate observations of the putrefactive process in
all their several varieties and situations; but the
loathsomeness and danger attending on such
inquiries hitherto greatly retarded our progress
in this department of chemical science.