The bones have hardly any animal properties in a natural state. Their
sensibility is nothing; the saw, the mallet, and the chisel act upon
their texture almost with impunity; an obscure feeling is the only
result of the action of these instruments; fire even can act upon them
without making the animal suffer much. But in a morbid state, the
sensibility is developed to the greatest extent; we know the horrible
pains that attend spina-ventosa, and those not less severe that caries
produces in certain cases. If a bone is inflamed, as for example the
sawed extremity of a stump after amputation, this bone which in a
natural state had borne, without transmitting any painful impression,
the action of the saw, becomes as it were a new sensitive organ, to
which the least touch is painful. The animal contractility is nothing
in the osseous system.
The organic properties give life to this system as to all the others.
The sensibility of this kind certainly exists in it; the fluids that
penetrate it are felt, and by virtue of this feeling, those are
appropriated to it which are proper for its nutrition. But is there
in the osseous system a reaction upon these fluids? are there those
insensible oscillations which compose insensible organic contractility?
Its hardness seems to prevent them. But yet the circulation is carried
on there; it performs a constant work, an habitual composition and
decomposition, which can hardly be conceived of without reaction on
the part of the osseous system. Besides this reaction is more slow,
more difficult on account of its structure; and hence without doubt
the slowness, of which we shall speak, in the vital phenomena of the
osseous system. Sensible organic contractility is foreign to it.
_Character of the Vital Properties._
The peculiar life of the bones is composed then of only two vital
properties, organic sensibility and insensible organic contractility.
From these two properties are derived all the vital phenomena
that these organs exhibit, inflammations, formation of tumours,
cicatrization of solutions of continuity, &c. This peculiar life is
remarkable in general, as I have just observed, when compared with
the peculiar lives of the other organs, by its slowness, by the tardy
concatenation of its phenomena. All things being equal as to ages, and
the different proportions of the earthy and cartilaginous substances,
inflammation is more slow there than in the other parts. Callus is
remarkable among the other cicatrices by the length of its formation;
compare an exostosis in its origin, its progress and its development,
with a tumour of the soft parts, a phlegmon for example, and you will
see the difference. Who does not know, that whilst suppuration often
requires only a few days in the other organs, it is whole months in
forming in the middle of the bones? Observe the difference that there
is between a gangrene of the soft parts, in which death takes place in
a short time, with caries and necrosis of the bones, in which a long
period elapses between disease and death of the part. In general we can
say, when inflammation exists in a bone, that it is chronic.
_Sympathies._
This character of the vital properties imprints an analogous one
upon the sympathetic relations of the osseous system with the other
systems. At first the animal contractility and the sensible organic
contractility cannot be put in action in these relations, as they do
not exist in the bones. The animal sensibility being developed in them
with difficulty and slowly by the diseases that essentially affect
them, the sympathies can be brought into action in them only in an
obscure manner. These sympathies then should act essentially upon the
organic sensibility and upon the insensible organic contractility, and
as these two properties are developed slowly, the different sympathies
should not be connected with the acute affections of the other organs,
and this is what is clearly proved by observation. In fact observe
that whilst many other systems respond with great quickness to the
acute diseases of an organ, this, as well as the cartilaginous,
fibro-cartilaginous systems, &c. remain then almost always in inaction.
Let the stomach, the lungs, the brain, &c. be the seat of a severe
acute disease, you see immediately many sympathetic phenomena arise in
the nervous, vascular, muscular, glandular, cutaneous, mucous systems,
&c. &c.; all seem to feel the trouble of the affected organ; each,
according to the vital forces that predominate there, exhibit different
phenomena, which are only aberrations, irregular developments of these
forces; in the animal muscular system, it is the animal contractility
which is especially raised; hence spasms and convulsions; in the
glandular, the serous, the cutaneous, the mucous, &c. the insensible
organic contractility and the organic sensibility principally
experience alterations; hence the different sympathetic derangements of
the secretions, of the sweat, of the exhalations; in the nervous, it
is the animal sensibility which is especially brought sympathetically
into action; hence the wandering or fixed pains in different parts;
in the organic muscular, it is the organic contractility which is
raised; hence the irregular motions of the heart, the stomach and the
intestines. In all the acute diseases of an organ there are always two
orders of symptoms, the one relative to the affected organ, as are the
cough, the pain in the side, the spitting of blood, the difficulty
of respiration, &c. in peripneumonia; the others purely sympathetic
and arising from the relations which connect the vitality of this
organ with that of all the others; now these last are often much more
numerous than the others.
Observe the bones in the midst of all that general sympathetic
derangement of the systems in which life is very active; they undergo
no alteration; their life, more slow than that of the other systems,
is not connected with these phenomena which have an acute character;
neither is that of the cartilages, the fibro-cartilages, the hair, the
aponeuroses, &c. All these systems, remarkable by the same character of
vitality, do not respond to the acute affections of the other systems;
they are not sympathetically affected, during these affections, at
least in an evident manner. Observe all the acute fevers; their
numerous phenomena have an effect only upon those systems in which
life is very active; those in which it is distinguished by an opposite
character, have uniformly no connexion with these phenomena; they are,
if we may so say, calm and tranquil in the midst of the tempest which
agitates the others. Let us take for example the different eruptions
that appear in fevers; it is upon the skin, the mucous surfaces, &c.
that they come; they arise during the fever and they disappear with it;
now the bones, the cartilages, &c. could not, from their kind of life,
admit of this sudden origin and disappearance.
It is then in the slow and chronic affections that we must seek for
examples of sympathies of the osseous, cartilaginous systems, &c. In
the first stages of the venereal disease, in which it is marked only
by acute symptoms, or in which at least its progress is not very slow,
as when it appears in buboes, in inflammations of the urethra, &c. it
has no influence upon the osseous system; it is only when it is of long
standing, when it has, as it were, degenerated, and become chronic,
that it makes the bones the seat of pains, of different tumours, &c.
Besides, I do not know, that we have yet thoroughly analyzed the
osseous sympathies. I have shown only their general character. We
shall understand them better, when we have given more attention to the
relation that there is in diseases between the affection of each organ,
and its kind of vitality.
_Seat of the Vital Properties._
The bones penetrated by saline substances which tend continually to
obey the laws of affinity and attraction, and to make these laws
predominate over those of sensibility and organic mobility, seem
to hold a middle place in living bodies, between these bodies and
inanimate ones. There is truly but one part of their osseous texture
which partakes of the vital phenomena, viz. their cartilaginous
substance; the other part or calcareous substance is foreign to them;
thus the proportion of each of these substances determines in the bones
their degree of life. In infancy, in which the first predominates, in
the early stages of the formation of callus, in which it is exclusively
found, in the softening of the bones in which it remains almost alone,
all the vital phenomena become more evident and more powerful. On the
contrary, as age accumulates in the bones the saline substance, as in
certain animals this accumulation takes place by the natural laws of
ossification in some external portions of the system with calcareous
base, as in the horns of stags, the shells of crustaceous animals,
&c. so life is, if we may so say, successively destroyed in the
bones; it becomes nothing, when this calcareous portion predominates
considerably; this is what happens in the necrosis which produces the
fall of the horns, the casting of the shells of crustaceous animals, &c.
Besides, that which shows the vital energy in an organ, is the
rapidity with which inflammation goes through its periods in it, and
the frequency of this affection, &c. Now in the bones inflammation
is so much the more rapid, in proportion to the greater quantity
of cartilaginous texture they contain; observe the periods of the
formation of the callus in the different ages, periods which are
determined by the duration of the inflammation necessary for its
formation, you will see that in infancy they are short, that they are
much longer in old age, and that often even consolidation does not take
place, whilst it is effected with facility in all the soft parts. The
general weakness no doubt of all the vital forces which takes place
from the effect of age is one cause of this slowness and this rapidity
in the formation of the callus at the two extreme periods of life;
but the different proportions of gelatinous and calcareous substances
contribute much to it also; for when we compare other cicatrices with
this, the cutaneous, for example, we see that age establishes in them
an infinitely less sensible difference as it respects the slowness and
rapidity of this reunion, than in the osseous system. The bones have
not sufficient life to inflame and unite, like the skin, the muscles
also exhibit this phenomenon in a very evident manner. I have seen
an old man, the neck of whose fractured thigh-bone remained a long
time without reunion, and in whom a wound of the face was healed very
speedily by the first intention.
Finally, there is a simple experiment that I have often made, and which
proves as well as the preceding facts, that the cartilage is truly
the animal part of the bone. We know that one of the great attributes
of animal substances, is to contract and exhibit the horny hardening
when burnt; now when the bone is penetrated with its earthy salt, it
has not this kind of combustion; deprived of this salt by an acid, the
cartilaginous parenchyma which remains burns in this manner. The flat
bones in infancy in which this parenchyma predominates, exhibits also
this phenomenon in burning; it forces the calcareous portion, which is
in small quantity to obey the impulse that it gives it, and turns it
in various directions; but in the adult in whom the calcareous portion
is the largest, the bone remains unmoved while the fire penetrates it,
and its whole cartilage is taken away, without its fibres being able to
obey their tendency to the horny hardening which combustion imprints
upon them.