General Anatomy, Applied to Physiology and Medicine, Vol. 2 (of 3)Bichat, Xavier
Science
General Anatomy, Applied to Physiology and Medicine, Vol. 2 (of 3)
Bichat, Xavier
Human anatomy; Human physiology
The existence of the saline substance in the bones is proved in
different ways. 1st. Combustion, by destroying the gelatinous portion,
leaves a friable, brittle body, of a form analogous to that of the bone
and which is nothing but this saline substance, which resembles, if
we may so say, a moulded body that keeps the form of the mould after
it has been taken away. If the combustion is pushed very far, and a
red heat produced on the calcined bones, they undergo a semi-fusion,
which makes them resemble the state of porcelain; they have then a
very compact, fine, semi-vitreous grain, a semi-transparency, and an
appearance like that of the vitrified earths. 2d. The long continued
exposure of the bones to the air produces an effect very similar to
that of the first degree of combustion, though however the gelatine
is rarely so thoroughly removed, and the saline portion so perfectly
exposed as by the action of fire. Besides, it requires a very long time
to produce this effect, especially upon the thick bones; the thin ones
are more easily altered; I have often made this observation. After ten
years exposure to the air and rain, I have observed that clavicles
taken from the cemetery of Clamart, exhibited upon the action of the
acids, a cartilaginous parenchyma almost equal to that of a bone that
had been some time dried. But this parenchyma finally disappears, and
the bone falls to powder, when it is no longer supported by it, and the
particles of the remaining calcareous substance have been disunited
by time. 3d. In the last stages of all cancerous diseases, the bones
have a friability which is only owing to the greater proportion of this
last substance, a proportion arising itself from the small quantity
of gelatine that is then exhaled in the bones. 4th. When a bone has
been for some time exposed to the action of an acid, the nitric for
example, a portion of its substance is taken from it by this acid,
which is evidently a calcareous salt, as can be seen by mixing it
with a solution of an alkali, which uniting immediately to the acid,
exposes this salt, by making it precipitate. 5th. Papins digester, by
dissolving by the action of water reduced to vapour the gelatinous
portion, shows also this saline calcareous part.
Scheele has found that this portion is a neutral salt with an earthy
base, the phosphate of lime. Frequently the phosphorus in fresh bones
give them a luminous appearance, that can be seen very far in the
night. It is sometimes the whole of the bone, sometimes some parts only
that become luminous. I have always observed in the illuminated places
an oily exudation, either that comes from the medullary juice, or is
furnished by the fat of the neighbouring soft parts of the bone.
Public-domain text, read in full here on John Shaqi.
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