The properties of texture are evident in the fibrous system, but they
are less so than in many others.
Extensibility is seen in the dura-mater, in hydrocephalus, in the
periosteum; in the different enlargements of which the bones are
susceptible; in the aponeuroses, in the swelling of the extremities,
and the distension of the abdominal parietes, which, as we know, are
aponeurotic as well as fleshy; in the fibrous capsules, in articular
dropsies; in the tunica sclerotica and albuginea in the swelling of
their respective organs.
This extensibility of the fibrous system is subjected to an uniform
law, which is unknown to the extensibility of most of the other
systems; it can only take place in a slow, gradual and insensible
manner. Thus when it is too quickly put into action, two different
phenomena take place, which equally suppose the impossibility of its
extending suddenly, as for example, a muscle, the skin, the cellular
texture, &c. do. 1st. If the fibrous organ makes a resistance greater
than the effort which it experiences, then it does not yield, and
different accidents result from it. We have many examples of this,
in the inflammatory swellings that appear under the aponeuroses of
the limbs, under those of the cranium, within the fibrous sheaths of
the tendons, &c. Then these fibrous organs not being able to stretch
with the same rapidity as the subjacent parts which swell, compress
painfully these swollen parts, and sometimes even expose them to
gangrene; this is what takes place in those strangulations so frequent
in surgical practice, and which require different operations to relieve
them. 2d. If the fibrous organ is inferior in its resistance to the
sudden effort which it experiences, it breaks instead of yielding;
hence the rupture of the tendons, the tearing of the fibrous capsules
and of the ligaments in luxations, that of the aponeuroses in certain
very rare cases reported by different authors, &c. &c. We easily
understand that the great resistance with which the fibrous texture is
endowed, is principally owing to the impossibility of yielding suddenly
to the impulse that is given to it.
In the slow and gradual extension of the fibrous organs, we observe
that often instead of becoming thinner and enlarging at the expense of
their thickness, they increase, on the contrary, in this dimension.
The albuginea of a scirrhous testicle, the sclerotica of a dropsical
or cancerous eye, the periosteum of a ricketty bone, &c. show us this
phenomenon, the reverse of which is sometimes observed, as in the
distensions of the abdominal aponeuroses produced by pregnancy, by
ascites, and also in hydrocephalus, &c.
The contractility of texture is accommodated in the fibrous system, to
the degree of its extensibility; as it cannot suddenly be distended,
it cannot suddenly contract when it ceases to be distended. This
fact is remarkable in the division of a tendon, of a portion of
aponeurosis, of a ligament laid bare in a living animal, in an
incision of the dura-mater, to discharge blood effused under it, &c. In
all these cases, the edges of the division undergo a separation hardly
perceptible; thus in the rupture of the tendons, the separation being
produced, not by the contraction of the divided extremities, but only
by the motions of the limb, the contact is effected by the position
in which in the natural state this tendon is not drawn: whilst in a
divided muscle, not only this position is necessary, but that in which
there is the greatest possible relaxation, and yet oftentimes contact
is not effected. If whilst a muscle is stretched, we cut its tendon
in a living animal, the end attached to the fleshy fibres separates a
little from the other by the retraction of these fibres; but that which
is attached to the bone remains immoveable, so that there is then but
one cause of separation to this, whereas there are two in a divided
fleshy part. If we cut a tendon when the muscle is relaxed, its ends
remain in place.
The contractility of texture is evident, however, at the end of some
time, in the fibrous system, especially when the organ has been first
stretched; for, when it is divided in its natural state, it is always
hardly any thing. The sclerotica after the puncture of the eye, or
after the amputation of the anterior half of this organ, and the
evacuation of its humours, the tunica albuginea, the peculiar coat of
the spleen and that of the kidney, after the resolution of a tumour
that had stretched their respective organs, the fibrous capsules
after the discharge of the fluid of articular dropsies, the abdominal
aponeuroses after the first and even the second accouchement, the
periosteum after the resolution of exostoses, &c. gradually contract
and resume their original forms.