Part 33

What is the nature of the fibrous texture? We know not, because we do not know any of its properties that are characteristic; it has only the negative ones of those of the muscular texture which is distinguished by contractility, and of those of the nervous texture which is characterized by sensibility. We always see it in a passive state; it obeys the action that is imparted to it, and has scarcely any of its own.

It establishes a great difference between the organs in which it exists and the skin, the cellular texture, the cartilages, the serous membranes, &c.; thus it was wrong to refer all these parts to one and the same class designated by the name of the white organs, a vague term that is only founded upon external appearances, upon the approximation of analyses yet incomplete, and not upon the texture, the vital properties, the life and the functions of the organs. Fourcroy foresaw that this extremely general division would be abandoned after further experiments.

However this may be, the following are the results which the fibrous texture gives when subjected to maceration, ebullition, drying, the action of the acids, &c.

Exposed to maceration in a moderate temperature, the fibrous texture remains a long time without undergoing any alteration; it preserves its size, form and density; gradually this last diminishes; the texture softens; but it does not dilate and swell up; its fibres can then be separated from each other; we see distinctly between them the cellular texture that unites them. Finally at the end of a very long time, they become changed into a soft, whitish pulp, which appears to be homogeneous. All the fibrous organs do not soften equally quick in this way. The tendons are the first to yield to maceration. Then come the aponeuroses; among these, those which are formed by the expansion of a tendon, soften quicker than those destined to cover the limbs, as the fascia lata, for example. The fibrous membranes, the capsules and the sheaths of the same nature are more resisting. Finally the ligaments yield the slowest to the action of water which tends to soften them; yet when they come originally from a tendon, as the inferior ligament of the patella, they are more easily macerated. I have made comparatively, experiments upon all these organs; they give the results that I have stated.

Every fibrous organ plunged into boiling water, or exposed to great heat, crisps and contracts like most of the other animal textures; it diminishes in size, hence it is more solid; it becomes elastic which it is not in the natural state, and afterwards it ceases to be so when it becomes softer before passing into the gelatinous state. By placing all the parts of this system at the same time in water which is made gradually to boil, we see that this softening comes upon all at the same degree, and with nearly the same force. This force, which tends then to make the fibres of this system contract is very considerable; it is sufficient to break at the place of their attachments, those of the periosteum which it raises, by this mechanism, from all the bones that have been boiled for a length of time; to detach the interosseous ligaments, the obturator membrane, &c. when we plunge them into boiling water, with the bones to which they adhere; to contract so strongly the articular surfaces against each other, that they cannot be moved, when, surrounded with their ligaments, they have been exposed to the concentrated action of caloric.

The fibrous texture gradually softens in water, becomes yellowish, semi-transparent and finally melts in part. By boiling together all the parts of the fibrous system, I have observed that the tendons soften first, then the aponeuroses, then the membranes, fibrous capsules and sheaths, and finally the ligaments, which are, as in maceration, those that yield last. Many have already made this remark, to which I add that all do not yield equally. Those placed between the layers of the vertebræ are the most tenacious; they do not take that yellow colour, that semi-transparency, common to all the fibrous system when boiled; they remain white and tough; they appear to contain much less gelatine, and to be entirely different in their nature.

Exposed to the action of the air, the fibrous system loses its whiteness by the evaporation of the fluids it contains; it acquires the horny hardening, becomes yellow, in part transparent and breaks with facility. Some days after having been dried, if replunged into water, it becomes nearly as white and soft as it was before; so that we can truly say, that its white colour is owing to water alone; this phenomenon takes place especially in the tendons. I have observed also in these last another remarkable phenomenon; it is that when they have macerated for some time, and are afterwards dried, they do not become yellow in drying, but remain of a very decided white. Without doubt the whole fibrous system would do the same.

The action of sulphuric and nitric acids quickly softens the fibrous texture, and reduces it to a kind of pulp, blackish in one and yellowish in the other; at the instant we plunge this texture into the acid, it crisps and contracts as in boiling water.

The fibrous texture resists in general putrefaction less than the cartilaginous; but it yields to it more slowly than the medullary, the cutaneous, the mucous, &c. In the midst of these putrid and disorganized textures in the subjects in our dissecting rooms, we find this still untouched; it finally becomes changed also. Water in which it has been macerated gives an odour less offensive than that which has been used for the maceration of most of the other systems.

More digestible than the cartilages and the fibro-cartilages, the fibrous texture is less so than most of the others. The experiments of Spallanzani and Gosse prove this. It appears that it yields to the action of the digestive juices in the same order as to maceration, ebullition, &c.; that is, 1st, the tendons; 2d, the aponeuroses; 3d, the different fibrous membranes; 4th, the ligaments, which are the most indigestible. I would observe however that when boiling has once softened the fibrous texture, it is all digested nearly alike. Thus the cartilages are as easy, and even more so, of digestion, than the tendons, when they have become gelatinous, as Spallanzani proved upon himself, though when raw they are much more indigestible.

II. Of the Common Parts which enter into the Organization of the Fibrous System.

The cellular texture exists in all the fibrous organs; but it is more or less abundant according as the fibres are more or less distant. In certain ligaments, it forms for the fibrous fasciæ, sheaths analogous to those of the muscles; in others, in the tendons, the aponeuroses, &c. we hardly perceive it; but everywhere it becomes very evident by maceration, by morbid affections, as, for example, by the fungi of the dura-mater, by the carcinoma of the testicle, which has seized the albuginea, by certain swellings of the periosteum, &c. In all these cases the fibrous texture relaxed, softened, preternatural, and of a spongy nature permits its fibres to separate and the cellular organ to appear. The development of fleshy granulations, the soft nature which these granulations have in certain wounds in which the fibrous organ is concerned, prove also the existence of the cellular organ there, which is in general in small quantity; this does not contribute a little to produce the resistance and the force of the organs that belong to it. Does this cellular texture contain fat? At first view we can hardly observe it, since we can scarcely distinguish this texture. Yet I have many times observed that by submitting to desiccation portions of aponeuroses, periosteum, dura-mater, &c. entirely stripped of every foreign part, when all these fluids had evaporated, and the organ had the appearance of parchment, a fatty exudation remaining on many places on its surface.

The existence of vessels varies in the fibrous system; much developed in some organs, as in the dura-mater, the periosteum, &c. they are less so in others, as the aponeuroses, and not at all in some, as the tendons. I would observe in general that it is in those in which they are the most evident, that inflammations and the different kinds of tumours are the most frequently observed. The affections of the dura-mater, the periosteum, &c. compared with those of the tendons, are a remarkable proof of this.

I do not know that absorbent vessels have been traced in the fibrous system.

The nerves appear to be equally foreign to it, notwithstanding what has been written on those of the periosteum, the dura-mater, &c. &c.

ARTICLE THIRD.

PROPERTIES OF THE FIBROUS SYSTEM.

I. Physical Properties.

The fibrous system has but a slight degree of elasticity in the natural state; but when its different organs are taken from the body and dried, they acquire it very considerably; thus the tendons, the aponeurotic expansions, &c. which in a fresh state would be incapable of any vibration, are found to resound in instruments when they are very dry.

II. Properties of Texture.

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.

III. Vital Properties.

There is never in the fibrous system animal contractility, nor sensible organic contractility. Organic sensibility and insensible organic contractility are found there as in all the other organs.