All the kinds of sympathies are observed in the fibrous system. Among the animal sympathies, the following are some of sensibility. 1st. In certain periostoses which occupy but a small surface, the whole of the periosteum of the bone that remains sound, becomes painful. 2d. After a puncture, or bruise of the periosteum, the whole of the limb often swells and becomes painful. 3d. In the affections of the dura-mater, the eye is frequently affected, and cannot bear the light, a phenomenon which may also depend on the communication of the cellular texture, but which is certainly sometimes sympathetic. 4th. When we make extension to reduce a luxation, and the articular ligaments consequently suffer much, the patient often complains of pain in a very distant part of the limb, &c.
Contractility is also brought into action in the animal sympathies of the fibrous system. 1st. The puncture of the centre of the diaphragm causes, it is said, in the facial muscles, a contraction which produces a sardonic smile. 2d. The injury of the aponeuroses, the stretching of the ligaments in the luxations of the foot and the tearing of the tendons, are frequently accompanied by convulsive motions of the jaws and even well marked tetanus. 3d. A splinter fixed in the dura-mater produces contractions in the different muscles of the economy. 4th. In injuries of the albuginea and the external aponeuroses, we often observe similar phenomena.
In the organic sympathies of the fibrous system, it is sometimes the insensible organic contractility that is brought into action, and sometimes the sensible organic contractility; the following are examples of the first. 1st. The dura-mater being inflamed, the inflammation which always supposes an increase of the tonic forces or of the insensible organic contractility, is often discoverable in the pericranium and vice versa. 2d. The irritation of a considerable extent of the periosteum often makes the medullary organ inflame and suppurate. 3d. The articular ligaments being stretched by twisting, all the neighbouring parts, and frequently the whole limb, swell and become a centre of irritation in which all the vital forces of life, insensible contractility in particular, are found much more raised than usual, &c.
At other times it is the sensible organic contractility which is brought into action. 1st. We often observe in the operation for cataract by depression, that the wound of the sclerotica occasions sympathetic vomitings, risings of the stomach, intestines, &c. 2d. A violent pain in any part, in the fibrous system in particular, increases very much the sensible organic contractility of the heart and thus produces from sympathy an acceleration in the motion which it gives to the blood. 3d. I have seen a man in whom Desault reduced a luxation, and who, from the great pain which the stretching of the ligaments gave him, was unable to retain his fœces, so great was the contraction of the rectum.
We see that in these sympathies, it is sometimes the fibrous system which exerts its influence upon the others, and sometimes they exert their action upon it. It is principally when it is drawn, when the peculiar kind of animal sensibility which it enjoys is put into action that it occasions in the whole economy a remarkable sympathetic derangement. I presume the ancients considered as nerves all the white parts, the ligaments, the tendons, &c. on account of the very serious accidents they had observed from their stretching in sprains, in complicated luxations of the knee, the elbow, the ankle, luxations which can never be produced without a violent stretching of many ligaments, of aponeurotic and tendinous parts, &c. A stroke of a sabre which divides the ligaments of the tarsus, a body which bruises them, produce consequences much less serious, than a false step that twists them. This leads us to an important general consideration, the truth of which is proved by the examination of the other systems; viz. that it is the predominant vital property in a system, which is especially brought into action by sympathies. As the animal sensibility, capable of responding to the agents of distension, is here the most strongly marked, it is this that performs the principal part in the fibrous sympathies.
ARTICLE FOURTH.
DEVELOPMENT OF THE FIBROUS SYSTEM.
I. State of the Fibrous System in the first age.
In the midst of the mucous state of the embryo, we cannot distinguish the fibrous organs. All is confounded; it is not until many other organs are formed, that we discover any traces of them. Those in the form of membranes appear at first like transparent nets; those arranged in fasciæ seem to be a homogeneous body. In general the fibres are not distinct in the first age; the aponeuroses, the fibrous membranes, the tendons, &c. do not exhibit any trace of them; all then seems to be uniform in the texture of the fibrous organs. In the fœtus of seven months, we begin to distinguish the white fibres. Few at first, and distant from each other, they gradually approximate after birth, are arranged in a parallel manner, or cross in different directions, according to the organ which they finally possess themselves of entirely at a certain age. It is especially on the phrenic centre of the diaphragm, the dura-mater, the aponeurosis of the thigh, that we easily make these observations.
As the fibres are developed in the fibrous organs, they have more resistance and hardness. In the fœtus and in the first years, they are extremely soft and easily yield. Their whiteness has a tinge wholly different from that of a more advanced age; they are of a pearly white. It is only gradually that they arrive at that degree of force that especially characterizes them.