Part 4

1st. Fire is the principal agent of this horny hardening. Every living organ, placed upon burning coals, is suddenly raised to the highest degree. 2d. Next to fire, the strongest acids, the sulphuric first, then the nitric, then the muriatic, make the animal fibres contract most suddenly. As they are diluted, they lose this power, and the acids that are naturally very weak have hardly any of it. 3d. Alkohol is much less powerful in producing this effect, though it may be highly concentrated. It contracts, however, the texture of parts, which it condenses and even twists. So that those who preserve anatomical specimens, find it necessary to dilute the alkohol. 4th. The neutral salts, after being moistened by the humidity of animal substances, condense and harden them wonderfully after the lapse of a considerable length of time. 5th. When the air has taken away, by drying, the aqueous particles of the solids, these continuing exposed to its action, contract, wrinkle, and twist in a slow and gradual manner. 6th. The alkalies, however strong they may be employed, do not produce any kind of horny hardening. 7th. Water appears to act in a manner opposite to this horny hardening; it dilates, spreads the organs by maceration, and separates their particles. It is when it is combined with much caloric that it produces horny hardening. This phenomenon takes place at some degrees below boiling, and is very remarkable at that point.

The different agents of which I have just spoken, produce, then, two species of horny hardening: 1st. the first is prompt, sudden, almost like the motion which results from the irritation of a living muscle: 2d. the other slow, gradual, and even insensible. Fire and the strong acids are in a special manner the agents of the first. The action of the neutral salts, of the air, of alkohol, principally produce the second.

These two species differ very much in their results. The state to which the first reduces the organ, is soon changed if the hardening cause continues. 1st. Fire continuing to act upon the solids, reduces them to a hard and coaly mass. 2d. Boiling water, after a length of time, destroys by degrees the hardness the solids had suddenly acquired, by being plunged into it. As the hardness diminishes, the effect of the boiling increases, and it arrives at the greatest extent, when the solid, having lost all consistence, becomes pulpy. 3d. Animal organs that have been acted upon suddenly by the acids, and become consequently hard, soon grow soft and change into a true pulp. This double phenomenon, that is presented on the one hand by boiling, and on the other by the strong acids, has a great analogy, and seems to be derived from the same principle.

The slow and insensible horny hardening, the effect of the contact of neutral salts, such as alum, the muriate of soda, &c. of the air and of alkohol, offers a very different phenomenon from the first. It is not altered by the continued action of the cause that produced it, however long it may be; it does not soften in a slow and insensible manner, as it has hardened, but remains always firm and contracted.

Are these two species only different degrees of the same, or are they derived from separate principles? I know not. I have only observed, that when the living solids have undergone the slow and gradual horny hardening, they are still susceptible of the other. We know that after many years drying, animal textures are hardened, as in a recent state, by the action of fire; I have made the same observation with regard to boiling and the acids. Textures that have been contracted for a long time by alkohol and the neutral salts present the same phenomenon.

All animal textures are susceptible of sudden hardening, except the hair, the epidermis, and the nails; these, if we may so say, exhibit only the rudiments of it. In general the hardening is more sensible, in proportion as the fibrous texture predominates in the organs. Hence the muscles, the tendons, and nerves, are the most susceptible of it. The organs not fibrous, as the glands, show the least degree of it. The slow and insensible horny hardening is almost the same in every part. Both exist in textures deprived of animal contractility, of sensible organic contractility, and of contractility of texture, as well as in those which enjoy them in the highest degree. Thus the tendons, the aponeuroses, the bones, even when their calcareous substance has been removed by acids, may be hardened as well as the muscles and the skin. This single circumstance would suffice to distinguish the contractility arising from hardening from all others, if a variety of differences, which I shall point out hereafter, under the article of the muscles in particular, did not.

When a texture is suddenly hardened, it loses more than half its length, and becomes twisted in various ways. Taken suddenly from the acid or boiling water, it remains hardened; but if it is pulled, it becomes elongated, and then contracts again, when the force applied ceases, so that it has acquired a real elasticity by the process of hardening. This elasticity is remarkable in the tendons, nerves and muscles, which before this are absolutely destitute of it. This elasticity is not an effect of the slow and insensible hardening of alkohol and the neutral salts. By macerating for a length of time the organized textures, they gradually lose the power of contracting suddenly, which does not, however, entirely disappear, until the maceration has reduced the textures to mere pulp.

If the textures are softened by boiling, and stretched out to their original length, after having been hardened, this cannot be produced again by any agent that we may employ.

When the textures are in a state of putrefaction, they no longer possess this kind of contractility.

Slow and insensible hardening cannot take place during life; this is an insurmountable obstacle to it. But that which is sudden may, when its agents have overcome the resistance that vitality offers. Oftentimes we see the skin hardened by burns. When it is stripped of its epidermis, and a very strong acid is poured upon it, the same effect is produced as upon any other organ.

When a part has been hardened upon a living subject, it almost inevitably dies; it cannot be restored to the suppleness that it possessed before; suppuration separates it from the sound parts.

The fluids do not present the phenomenon of hardening, the fibrine only excepted. Separated from the blood, it crisps and contracts.

After what has been said, it is evident that the solids possess the faculty of contracting or shortening. This is brought into action in many different ways. During life it appears, 1st. in the influence of the nerves upon the voluntary muscles; this is animal contractility. 2d. In the involuntary muscles by the action of stimuli; this is sensible organic contractility. 3d. In the muscles, the skin, the cellular texture, the arteries, the veins, &c. from a want of extension. This is the contractility of texture, which is not found, or at least is very obscure, in many of the organs, as the nerves, the fibrous bodies, the cartilages, the bones, &c. 4th. By the action of fire, and the strong acids; this is the contractility of the horny hardening, and is general.

When the muscles are deprived of life, they lose the two first kinds of contractility; but the third remains with them as it does with all the organs that enjoy it. When they are dried or remain in water a little time, they lose that also; but the fourth still continues with them; it is the last that abandons the animal textures; it is perpetuated for a length of years. When I have exposed to the action of fire the cartilaginous parenchyma of bones found in cemeteries, they have become hardened. I am persuaded that this faculty would last for many ages, if we could preserve the organic textures.

Contractility is, then, a common and general property, inherent in all animal textures, but which, according to the manner that it is brought into action, presents essential differences, which divide it into many species, that have no analogy. It would certainly be impossible to avoid distinguishing the difference between the four species I have pointed out, and that insensible contraction, or kind of oscillation, which forms during life the insensible organic contractility, or tonic motions.

Among the causes that bring contractility into action, some belong, then, to life, others are independent of it, and are derived only from organization. All the organs are essentially contractile; but each of the causes which makes them contract acts only upon this or that texture: the horny hardening alone has a general effect.

VI. _Observations upon the organization of animals._

The properties, whose influence we have just analyzed, are not absolutely inherent in the particles of matter that are the seat of them. They disappear when these scattered particles have lost their organic arrangement. It is to this arrangement that they exclusively belong; let us treat of it here in a general way.

All animals are an assemblage of different organs, which, executing each a function, concur in their own manner, to the preservation of the whole. It is several separate machines in a general one, that constitutes the individual. Now these separate machines are themselves formed by many textures of a very different nature, and which really compose the elements of these organs. Chemistry has its simple bodies, which form, by the combinations of which they are susceptible, the compound bodies; such are caloric, light, hydrogen, oxygen, carbon, azote, phosphorus, &c. In the same way anatomy has its simple textures, which, by their combinations four with four, six with six, eight with eight, &c. make the organs. These textures are, 1st. the cellular; 2d. the nervous of animal life; 3d. the nervous of organic life; 4th. the arterial; 5th. the venous; 6th. the texture of the exhalants; 7th. that of the absorbents and their glands; 8th. the osseous; 9th. the medullary; 10th. the cartilaginous; 11th. the fibrous; 12th. the fibro-cartilaginous; 13th. the muscular of animal life; 14th. the muscular of organic life; 15th. the mucous; 16th. the serous; 17th. the synovial; 18th. the glandular; 19th. the dermoid; 20th. the epidermoid; 21st. the pilous.

These are the true organized elements of our bodies. Their nature is constantly the same, wherever they are met with. As in chemistry, the simple bodies do not alter, notwithstanding the different compound ones they form. The organized elements of man form the particular object of this work.

The idea of thus considering abstractedly the different simple textures of our bodies, is not the work of the imagination; it rests upon the most substantial foundation, and I think it will have a powerful influence upon physiology as well as practical medicine. Under whatever point of view we examine them, it will be found that they do not resemble each other; it is nature and not science that has drawn the line of distinction between them.

1st. Their forms are every where different; here they are flat, there round. We see the simple textures arranged as membranes, canals, fibrous fasciæ, &c. No one has the same external character with another, considered as to their attributes of thickness or size. These differences of form, however, can only be accidental, and the same texture is sometimes seen under many different appearances; for example, the nervous appears as a membrane in the retina, and as cords in the nerves. This has nothing to do with their nature; it is then from the organization and the properties, that the principal differences should be drawn.

2dly. There is no analogy in the organization of the simple textures. We shall see that this organization results from parts that are common to all, and from those that are peculiar to each; but the common parts are all differently arranged in each texture. Some unite in abundance the cellular texture, the blood vessels and the nerves; in others, one or two of these three common parts are scarcely evident or entirely wanting. Here there are only the exhalants and absorbents of nutrition; there the vessels are more numerous for other purposes. A capillary net-work, wonderfully multiplied, exists in certain textures, in others this net-work can hardly be demonstrated. As to the peculiar part, which essentially distinguishes the texture, the differences are striking. Colour, thickness, hardness, density, resistance, &c. nothing is similar. Mere inspection is sufficient to show a number of characteristic attributes of each, clearly different from the others. Here is a fibrous arrangement, there a granulated one; here it is lamellated, there circular. Notwithstanding these differences, authors are not agreed as to the limits of the different textures. I have had recourse, in order to leave no doubt upon this point, to the action of different re-agents. I have examined every texture, submitted them to the action of caloric, air, water, the acids, the alkalies, the neutral salts, &c. drying, putrefaction, maceration, boiling, &c. the products of many of these actions have altered in a different manner each kind of texture. Now it will be seen that the results have been almost all different, that in these various changes, each acts in a particular way, each gives results of its own, no one resembling another. There has been considerable inquiry to ascertain whether the arterial coats are fleshy, whether the veins are of an analogous nature, &c. By comparing the results of my experiments upon the different textures, the question is easily resolved. It would seem at first view that all these experiments upon the intimate texture of systems, answer but little purpose; I think however that they have effected an useful object, in fixing with precision the limits of each organized texture; for the nature of these textures being unknown, their difference can be ascertained only by the different results they furnish.

3dly. In giving to each system a different organic arrangement, nature has also endowed them with different properties. You will see in the subsequent part of this work, that what we call _texture_ presents degrees infinitely varying, from the muscles, the skin, the cellular membrane, &c. which enjoy it in the highest degree, to the cartilages, the tendons, the bones, &c. which are almost destitute of it. Shall I speak of the vital properties? See the animal sensibility predominant in the nerves, contractility of the same kind particularly marked in the voluntary muscles, sensible organic contractility, forming the peculiar property of the involuntary, insensible contractility and sensibility of the same nature, which is not separated from it more than from the preceding, characterizing especially the glands, the skin, the serous surfaces, &c. &c. See each of these simple textures combining, in different degrees, more or less of these properties, and consequently living with more or less energy.

There is but little difference arising from the number of vital properties they have in common; when these properties exist in many, they take in each a peculiar and distinctive character. This character is chronic, if I may so express myself, in the bones, the cartilages, the tendons, &c.; it is acute in the muscles, the skin, the glands, &c.

Independently of this general difference, each texture has a particular kind of force, of sensibility, &c. Upon this principle rests the whole theory of secretion, of exhalation, of absorption, and of nutrition. The blood is a common reservoir, from which each texture chooses, that which is adapted to its sensibility, to appropriate and keep it, or afterwards reject it.

Much has been said since the time of Bordeu, of the peculiar life of each organ, which is nothing else than that particular character which distinguishes the combination of the vital properties of one organ, from those of another. Before these properties had been analyzed with exactness and precision, it was clearly impossible to form a correct idea of this peculiar life. From the account I have just given of it, it is evident that the greatest part of the organs being composed of very different simple textures, the idea of a peculiar life can only apply to these simple textures, and not to the organs themselves.

Some examples will render this point of doctrine which is important, more evident. The stomach is composed of the serous, organic muscular, mucous, and of almost all the common textures, as the arterial, the venous, &c. which we can consider separately. Now if you should attempt to describe in a general manner, the peculiar life of the stomach it is evidently impossible that you could give a very precise and exact idea of it. In fact the mucous surface is so different from the serous, and both so different from the muscular, that by associating them together, the whole would be confused. The same is true of the intestines, the bladder, the womb, &c.; if you do not distinguish what belongs to each of the textures that form the compound organs, the term peculiar life will offer nothing but vagueness and uncertainty. This is so true, that oftentimes the same textures alternately belong or are foreign to their organs. The same portion of the peritoneum, for example, enters or does not enter, into the structure of the gastric viscera, according to their fulness or vacuity.

Shall I speak of the pectoral organs? What has the life of the fleshy texture of the heart in common with that of the membrane that surrounds it? Is not the pleura independent of the pulmonary texture? Has this texture nothing in common with the membrane that surrounds the bronchia? Is it not the same with the brain in relation to its membranes, of the different parts of the eye, the ear, &c.?

When we study a function, it is necessary carefully to consider in a general manner, the compound organ that performs it; but when you wish to know the properties and life of this organ, it is absolutely necessary to decompose it. In the same way, if you would have only general notions of anatomy, you can study each organ as a whole; but it is essential to separate the textures, if you have a desire to analyze with accuracy its intimate structure.

VII. _Consequences of the preceding principles relative to diseases._

What I have been saying leads to important consequences, as it respects those acute or chronic diseases that are local; for those, which like most fevers, affect almost simultaneously every part, cannot be much elucidated by the anatomy of systems. The first then will engage our attention.

Since diseases are only alterations of the vital properties, and each texture differs from the others in its properties, it is evident there must be a difference also in the diseases. In every organ then, composed of different textures, one may be diseased, while the others remain sound; now this happens in a great many cases; let us take the principal organs, for example.

1st. Nothing is more rare than affections of the mass of the brain; nothing is more common than inflammation of the tunica arachnoides that covers it. 2d. Oftentimes one membrane of the eye only is affected, the others preserving their ordinary degree of vitality. 3d. In convulsions or paralysis of the muscles of the larynx, the mucous surface is unaffected; and on the other hand the muscles perform their functions as usual in catarrhs of this surface. Both these affections are foreign to the cartilages, and vice versa. 4th. We observe a variety of different alterations in the texture of the pericardium, but hardly ever in that of the heart itself; it remains sound while the other is inflamed. The ossification of the common membrane of the red blood does not extend to the neighbouring textures. 5th. When the membrane of the bronchia is the seat of catarrh, the pleura is hardly affected at all, and reciprocally in pleurisy the first is scarcely ever altered. In peripneumony, when an enormous infiltration in the dead body shows the excessive inflammation that has existed during life in the pulmonary texture, the serous and mucous surfaces often appear not to have been affected. Those who open dead bodies know that they are frequently healthy in incipient phthisis. 6th. We speak of a bad stomach, a weak stomach; this most commonly should be understood as applying to the mucous surface only. Whilst this secretes with difficulty the nutritive juices, without which digestion is impaired, the serous surface exhales as usual its fluid, the muscular coat continues to contract, &c. In ascites, in which the serous surface exhales more lymph than in a natural state, the mucous oftentimes performs its functions perfectly well, &c. 7th. All authors have said much of the inflammation of the stomach, the intestines, the bladder, &c. For myself I believe that this disease rarely ever affects at first the whole of any of these organs, except in the case where poison or some other deleterious substance acts upon them. There are for the mucous surface of the stomach and intestines, acute and chronic catarrhs, for the peritoneum serous inflammations, perhaps even for the layer of organic muscles that separates the two membranes, there is a particular kind of inflammation, though we have as yet hardly any thing certain upon this point; but the stomach, the intestines, and the bladder are not suddenly affected with these three diseases. A diseased texture can affect those near it, but the primitive affection seizes only upon one. I have examined a great number of bodies in which the peritoneum was inflamed either upon the intestines, the stomach, the pelvis, or universally; now very often when this affection is chronic, and almost always when it is acute, the subjacent organs remain sound. I have never seen this membrane exclusively diseased upon one organ, while that of the neighbouring ones remain untouched; its affection is propagated more or less remotely. I know not why authors have hardly ever spoken of its inflammation, and have placed to the account of the subjacent viscera that which most often belongs only to this. There are almost as many cases of peritonitis as of pleurisy, and yet while these last have been particularly noticed the others are almost entirely overlooked. Oftentimes that part of the peritoneum corresponding to an organ, is much inflamed; we see it in the case of the stomach; we observe especially after the suppression of the lochia or the menses, that it is the portion that lines the pelvis that is first affected. But soon the affection becomes more or less general; at least examinations after death prove it satisfactorily. 8th. Certainly the acute or chronic catarrh of the bladder, or womb even, has nothing in common with the inflammation of that portion of the peritoneum corresponding with these organs. 9th. Every one knows that diseases of the periosteum have oftentimes no connexion with the bone, and vice versa, that frequently the marrow is for a long time affected, while both the others remain sound. There is no doubt that the osseous, medullary and fibrous textures have their peculiar affections which we shall not confound with the idea we may form of the diseases of the bones. The same can be said of the intestines, of the stomach, &c. in relation to their mucous, serous, muscular textures, &c. 10th. Though the muscular and tendinous textures are combined in a muscle, their diseases are very different. 11th. You must not think that the synovial is subject to the same diseases as the ligaments that surround it, &c.