General Anatomy, Applied to Physiology and Medicine, Vol. 2 (of 3)

by Xavier Bichat

The bones have hardly any animal properties in a natural state. Their sensibility is nothing; the saw, the mallet, and the chisel act upon their texture almost with impunity; an obscure feeling is the only result of the action of these instruments; fire even can act upon them without making the animal suffer much. But in a morbid state, the sensibility is developed to the greatest extent; we know the horrible pains that attend spina-ventosa, and those not less severe that caries produces in certain cases. If a bone is inflamed, as for example the sawed extremity of a stump after amputation, this bone which in a natural state had borne, without transmitting any painful impression, the action of the saw, becomes as it were a new sensitive organ, to which the least touch is painful. The animal contractility is nothing in the osseous system.

The organic properties give life to this system as to all the others. The sensibility of this kind certainly exists in it; the fluids that penetrate it are felt, and by virtue of this feeling, those are appropriated to it which are proper for its nutrition. But is there in the osseous system a reaction upon these fluids? are there those insensible oscillations which compose insensible organic contractility? Its hardness seems to prevent them. But yet the circulation is carried on there; it performs a constant work, an habitual composition and decomposition, which can hardly be conceived of without reaction on the part of the osseous system. Besides this reaction is more slow, more difficult on account of its structure; and hence without doubt the slowness, of which we shall speak, in the vital phenomena of the osseous system. Sensible organic contractility is foreign to it.

Character of the Vital Properties.

The peculiar life of the bones is composed then of only two vital properties, organic sensibility and insensible organic contractility. From these two properties are derived all the vital phenomena that these organs exhibit, inflammations, formation of tumours, cicatrization of solutions of continuity, &c. This peculiar life is remarkable in general, as I have just observed, when compared with the peculiar lives of the other organs, by its slowness, by the tardy concatenation of its phenomena. All things being equal as to ages, and the different proportions of the earthy and cartilaginous substances, inflammation is more slow there than in the other parts. Callus is remarkable among the other cicatrices by the length of its formation; compare an exostosis in its origin, its progress and its development, with a tumour of the soft parts, a phlegmon for example, and you will see the difference. Who does not know, that whilst suppuration often requires only a few days in the other organs, it is whole months in forming in the middle of the bones? Observe the difference that there is between a gangrene of the soft parts, in which death takes place in a short time, with caries and necrosis of the bones, in which a long period elapses between disease and death of the part. In general we can say, when inflammation exists in a bone, that it is chronic.

Sympathies.

This character of the vital properties imprints an analogous one upon the sympathetic relations of the osseous system with the other systems. At first the animal contractility and the sensible organic contractility cannot be put in action in these relations, as they do not exist in the bones. The animal sensibility being developed in them with difficulty and slowly by the diseases that essentially affect them, the sympathies can be brought into action in them only in an obscure manner. These sympathies then should act essentially upon the organic sensibility and upon the insensible organic contractility, and as these two properties are developed slowly, the different sympathies should not be connected with the acute affections of the other organs, and this is what is clearly proved by observation. In fact observe that whilst many other systems respond with great quickness to the acute diseases of an organ, this, as well as the cartilaginous, fibro-cartilaginous systems, &c. remain then almost always in inaction. Let the stomach, the lungs, the brain, &c. be the seat of a severe acute disease, you see immediately many sympathetic phenomena arise in the nervous, vascular, muscular, glandular, cutaneous, mucous systems, &c. &c.; all seem to feel the trouble of the affected organ; each, according to the vital forces that predominate there, exhibit different phenomena, which are only aberrations, irregular developments of these forces; in the animal muscular system, it is the animal contractility which is especially raised; hence spasms and convulsions; in the glandular, the serous, the cutaneous, the mucous, &c. the insensible organic contractility and the organic sensibility principally experience alterations; hence the different sympathetic derangements of the secretions, of the sweat, of the exhalations; in the nervous, it is the animal sensibility which is especially brought sympathetically into action; hence the wandering or fixed pains in different parts; in the organic muscular, it is the organic contractility which is raised; hence the irregular motions of the heart, the stomach and the intestines. In all the acute diseases of an organ there are always two orders of symptoms, the one relative to the affected organ, as are the cough, the pain in the side, the spitting of blood, the difficulty of respiration, &c. in peripneumonia; the others purely sympathetic and arising from the relations which connect the vitality of this organ with that of all the others; now these last are often much more numerous than the others.

Observe the bones in the midst of all that general sympathetic derangement of the systems in which life is very active; they undergo no alteration; their life, more slow than that of the other systems, is not connected with these phenomena which have an acute character; neither is that of the cartilages, the fibro-cartilages, the hair, the aponeuroses, &c. All these systems, remarkable by the same character of vitality, do not respond to the acute affections of the other systems; they are not sympathetically affected, during these affections, at least in an evident manner. Observe all the acute fevers; their numerous phenomena have an effect only upon those systems in which life is very active; those in which it is distinguished by an opposite character, have uniformly no connexion with these phenomena; they are, if we may so say, calm and tranquil in the midst of the tempest which agitates the others. Let us take for example the different eruptions that appear in fevers; it is upon the skin, the mucous surfaces, &c. that they come; they arise during the fever and they disappear with it; now the bones, the cartilages, &c. could not, from their kind of life, admit of this sudden origin and disappearance.

It is then in the slow and chronic affections that we must seek for examples of sympathies of the osseous, cartilaginous systems, &c. In the first stages of the venereal disease, in which it is marked only by acute symptoms, or in which at least its progress is not very slow, as when it appears in buboes, in inflammations of the urethra, &c. it has no influence upon the osseous system; it is only when it is of long standing, when it has, as it were, degenerated, and become chronic, that it makes the bones the seat of pains, of different tumours, &c. Besides, I do not know, that we have yet thoroughly analyzed the osseous sympathies. I have shown only their general character. We shall understand them better, when we have given more attention to the relation that there is in diseases between the affection of each organ, and its kind of vitality.

Seat of the Vital Properties.

The bones penetrated by saline substances which tend continually to obey the laws of affinity and attraction, and to make these laws predominate over those of sensibility and organic mobility, seem to hold a middle place in living bodies, between these bodies and inanimate ones. There is truly but one part of their osseous texture which partakes of the vital phenomena, viz. their cartilaginous substance; the other part or calcareous substance is foreign to them; thus the proportion of each of these substances determines in the bones their degree of life. In infancy, in which the first predominates, in the early stages of the formation of callus, in which it is exclusively found, in the softening of the bones in which it remains almost alone, all the vital phenomena become more evident and more powerful. On the contrary, as age accumulates in the bones the saline substance, as in certain animals this accumulation takes place by the natural laws of ossification in some external portions of the system with calcareous base, as in the horns of stags, the shells of crustaceous animals, &c. so life is, if we may so say, successively destroyed in the bones; it becomes nothing, when this calcareous portion predominates considerably; this is what happens in the necrosis which produces the fall of the horns, the casting of the shells of crustaceous animals, &c.