is solution, whether made
with fibrine or albumen, has the very same re-actions with all
substances yet tried.
Both albumen and fibrine, in the process of nutrition, are capable
of being converted into muscular fibre, and muscular fibre is
capable of being reconverted into blood. These facts have long been
established by physiologists, and chemistry has merely proved that
these metamorphoses can be accomplished under the influence of a
certain force, without the aid of a third substance, or of its
elements, and without the addition of any foreign element, or the
separation of any element previously present in these substances.
If we now compare the composition of all organised parts with that
of fibrine and albumen, the following relations present themselves:--
All parts of the animal body which have a decided shape, which form
parts of organs, contain nitrogen. No part of an organ which
possesses motion and life is destitute of nitrogen; all of them
contain likewise carbon and the elements of water; the latter,
however, in no case in the proportion to form water.
The chief ingredients of the blood contain nearly 17 per cent. of
nitrogen, and from numerous analyses it appears that no part of an
organ contains less than 17 per cent. of nitrogen.
The most convincing experiments and observations have proved that
the animal body is absolutely incapable of producing an elementary
body, such as carbon or nitrogen, out of substances which do not
contain it; and it obviously follows, that all kinds of food fit for
the production either of blood, or of cellular tissue, membranes,
skin, hair, muscular fibre, &c., must contain a certain amount of
nitrogen, because that element is essential to the composition of
the above-named organs; because the organs cannot create it from the
other elements presented to them; and, finally, because no nitrogen
is absorbed from the atmosphere in the vital process.
The substance of the brain and nerves contains a large quantity of
albumen, and, in addition to this, two peculiar fatty acids,
distinguished from other fats by containing phosphorus (phosphoric
acid?). One of these contains nitrogen (Fremy).
Finally, water and common fat are those ingredients of the body
which are destitute of nitrogen. Both are amorphous or unorganised,
and only so far take part in the vital process as that their
presence is required for the due performance of the vital functions.
The inorganic constit
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