Extensibility is very often brought into action in the
fibro-cartilaginous system. I have seen a polypus that had so dilated
the anterior openings and consequently the fibro-cartilages of the
nostrils, that their diameter was at least treble. The external and
cartilaginous extremity of the meatus auditorius often exhibits from
the same cause, an analogous distension. In the various twistings of
the vertebral column, the portion of the fibro-cartilages corresponding
to the convexity of the curvatures, is evidently elongated, whilst
the opposite portion is contracted. This extensibility is moreover
subjected in many cases to the same law as in the fibrous system,
that is to say that it cannot be put into action but in a gradual and
insensible manner.
The contractility of texture is observed when, in the cases of which
I have spoken, the cause of distension disappears. Thus after the
extraction of the polypus mentioned, the nostril gradually resumes its
natural diameter. I have removed in a dog a tendon from its groove,
by cutting it at one extremity, and drawing it by the other, so as to
leave untouched and empty the sheath that contained it; this sheath
and the fibro-cartilage have gradually contracted and the cavity has
disappeared. In the carcinoma of the eye, in which the eye-lids were
not removed, the tarsi which become much elongated with these moveable
veils, gradually contract and resume their dimensions, after the
extirpation of the tumour which distended them. It is necessary however
to distinguish these phenomena from those which are the product of
elasticity; these last are prompt and sudden; the fibro-cartilage of
the ear, powerfully stretched, yields a little, and immediately goes
back again; the others, on the contrary, are characterized most often
by a remarkable slowness.