All the vital properties appear to be but little developed in the
fibro-cartilages; there is no animal sensibility or contractility in
the natural state; the first appears however in inflammation. Organic
sensibility and insensible contractility are only found in the degree
necessary for nutrition. There is no sensible organic contractility.
This obscurity in the vital properties, gives to all the phenomena
of the life of the organs of which we are treating, a remarkable
slowness. I have observed that in making in the ears of a dog a
longitudinal section, and afterwards uniting the wound by a suture,
the skin, at the end of a few days, is entirely closed; but it is
only at the expiration of a much longer time, that the union of the
cartilage takes place below, as we can see by examining the parts after
the union of the integuments. I presume that the same thing happened
in the operation of tracheotomy formerly employed, in which the soft
parts forming at first the cicatrix, keep in contact the cartilaginous
semi-rings, which finally unite together.
It is also to this obscurity of the vital properties of the
fibro-cartilages, to their want of energy, that must undoubtedly be
referred the rareness of diseases of these organs. I know but few of
the organic systems in the economy, which are more rarely affected than
that of the fibro-cartilages of the nose, of the ears, the trachea, &c.
Gangrene attacks them with difficulty; they are scarcely altered by it,
whilst the soft parts which surround them are all already black. We
know but little of the kind of fluid they form in their suppuration.
The formation of pus appears to be even very rare in them, owing to
their want of vital activity.
As these organs are hardly ever diseased, we can with difficulty know
their sympathies; I am unable to cite an example of them.