Chapter VI: Section II (1)

┌1st. Of the vital properties.
│ ┌Animal properties ┌Sensibility.
│ │ │Contractility.
│2d. Division of the vital │
│ properties │Organic ┌Sensibility.
│ └ properties │Sensible and insensible
│ └ contractility.
│3d. Characters of the vital properties. ┌Habit.
│ │Sex.
│4th. Of the causes which modify the │Climate.
│ vital properties │Seasons.
│ └Age, &c.
│
│5th. Of the peculiar differences of the vital ┌Of that which is called
│ properties, in each simple texture, in each └ individual life.
│ individual
│ ┌Of temperament.
│6th. Of the general differences of the vital │Of the passions.
│ properties in different individuals └Of the character.
│
│7th. Sympathies of vital properties. ┌Animal sympathies ┌Of sensibility.
│ │ └Of contractility.
└8th. Division of sympathies │ ┌Of sensible
└Organic sympathies │ contractility.
│Of insensible
└ contractility.

OF THE FUNCTIONS.

FIRST CLASS.—FUNCTIONS RELATIVE TO THE INDIVIDUAL.

ORDER FIRST.—_Functions of Animal Life._

GENUS I. _Sensations._
┌1st. Of the general sensations, or feeling, ┌external.
│ └internal.
│ ┌Hearing.
│ │Seeing.
│2d. Of particular sensations │Smelling.
│ │Tasting
│ └Feeling.
└3d. Of pleasure and of pain.

GENUS II. _Cerebral Functions._

┌Of perception.
┌1st. Relative to sensation │Of imagination.
│ └Of memory.
│ ┌Of attention.
│ │Of the ideas.
│2d. Relative to the understanding │Of the judgment.
│ └Of the reasoning faculty, &c.
│
│ ┌Of the will, ┌the ┌Of the
│3d. Relative to motion │which is │ judgment. │ opposition
│ └determined by │the │ of these two
│ └ passions. └ causes.
│
└4th. Connexion of the cerebral functions with life ┌Of concussion.
└Of apoplexy, &c.

GENUS III. _Locomotion._
┌on the feet Standing.
┌ │on the knees.
│1st. Of the immoveable attitudes │on the pelvis.
│ │on the head, &c. &c.
│ └—Prostration.
│
│ ┌ ┌ Prepulsion.
│ │ │ Repulsion.
│ │Of the superior │ Diduction.
│ │ extremities. │ Pressure.
│ │ └ Elevation, &c.
│ │ ┌Walking.
└2d. Motion │Of the inferior │Running.
│ extremities. └Leaping.
│Of the trunk. Support, raising weights.
│Of the whole body. Swimming.
│ ┌1st. Gestures of the face.
│Of gesture considered │2d. Gestures of the head in
│ as an auxiliary │ general.
└ to the voice. │3d. Gestures of the superior
└ extremities.

GENUS IV. _Voice._
┌1st. Of the voice of brutes Dumbness.
│2d. Of speech. ┌Of stuttering.
│ └Of lisping, &c.
│
│3d. Of singing ┌true.
│ └false.
└4th. Of declamation.

GENUS V. _Nervous transmission._
┌1st. Transmission to the brain of sensations ┌general.
│ └particular.
│2d. Transmission of motion ┌to the locomotive organs.
│ └to the vocal organs.
└3d. Mode of transmission.

OF THE INTERMISSION OF THE FUNCTIONS OF ANIMAL LIFE.

_Sleep._
┌partial ┌of the senses.
┌ 1st. natural. │ │of the brain ... Of sympathetic sleep.
│ │ └of the muscles.
│ └general.
│ 2d. unnatural.
└ 3d. Dreams and somnambulism.

ORDER SECOND.—_Functions of organic life._

GENUS I. _Digestion._
┌1st. Of hunger and thirst.
│2d. Of aliments.
│3d. Of taking of aliments ┌solid.
│ └fluid.
│4th. Of mastication, of lubricating with saliva and deglutition.
│ ┌in the œsophagus. Action of the liquor of the
│ │ œsophagus.
│5th. Alteration of │in the stomach. Action of the gastric liquor.
│ the alimentary mass. │in the small ┌Action of the bile.
│ └ intestines │Action of the pancreatic liquor.
│ └Action of the intestinal liquor.
│
│6th. Separation of the substances that are nutritive from those
│ that are not.
│ ┌the lacteals.
│7th. Absorption of the nutritive substance; │the mesenteric glands,
│ course of the chyle in │the thoracic duct.
│ └the blood vessels.
│8th. Excretion of the non-nutritive ┌Of the peristaltic motion.
│ substance │Of the fecal matter.
│ └Of the intestinal gas.
│ ┌the pharynx and œsophagus.
│ │the stomach.
└9th. Of vomiting, as it has its seat in │the small intestines.
│the large intestines.
└—Sympathetic vomiting.

GENUS II. _Respiration._
┌1st. Of the air.
│2d. Mechanical phenomena ┌Inspiration.
│ └Expiration.
│3d. Chemical Phenomena relative ┌to the air.
│ └to the blood.
└4th. Connexion of respiration with life. Of asphyxia, &c.

GENUS III. _Circulation._
┌Circulation of red blood.
│Circulation of black blood.
┌1st. general │Action of the heart.
│ │Action of the arteries.
│ │Action of the veins.
│ │Connexion of the circulation with life.
│ └ Of syncope, &c.
│2d. abdominal.
│ ┌phenomena of the motion of the blood.
│ ┌general └change of red to black.
└3d. capillary │ ┌its relation with the general.
└pulmonary └change of black to red blood.

GENUS IV. _Exhalations._
┌of their agents.
┌1st. in general │of their phenomena.
│ │of their alterations.
│ └—Sympathetic exhalations.
│ ┌serous.
│ │cellular ┌of fat.
│ │ └of serum.
│2d. in particular. │synovial ┌in the grooves of the tendons.
└ Exhalations │ └in the articulations.
│ ┌in the middle of the long bones.
└medullary │in the extremities of the long bones,
└ in the short and flat ones.

GENUS V. _Absorptions._
┌Of their agents.
┌1st. in general │Of their phenomena.
│ │Of their alterations.
│ └—Sympathetic absorptions.
│ ┌serous.
│ │cellular ┌ of fat.
│2d. in particular. │ └ of serum.
└ Absorptions │synovial ┌ in the grooves of the tendons.
│ └ in the articulations.
│ ┌ in the middle of the long bones.
└medullary │ in the extremities of the long bones,
└ in the short and flat ones.

GENUS VI. _Secretions._
┌Of their agents.
┌1st. in general │Of their phenomena.
│ │Of their alterations.
│ └—Sympathetic secretions.
│ ┌lachrymal.
│ │salivary and pancreatic.
│ │hepatic.
└2d. in particular. Secretions │renal.
│mucous.
└sebaceous.

GENUS VII. _Nutrition._
┌1st. Of the double nutritive motion.
│ ┌Nutritive matter, ┌ the chyle.
│2d. Composition of organs │ considered in ...│ the blood.
│ └—Assimilation. └ the organs themselves.
│
│3d. Decomposition of organs.
│4th. Causes that modify nutrition.
│ ┌infancy Of increase in height.
│5th. Of nutrition considered in │youth Of increase in thickness.
│ │adult age.
│ └old age Decrease.
└ 6th. Of natural death.

GENUS VIII. _Calorification._
┌1st. Phenomena of animal heat.
│ ┌respiration.
│ 2d. Entrance of caloric by │digestion.
│ └absorption.
│ 3d. Its latent state in the blood.
│ 4th. Its disengagement in the capillary system.
│ 5th. Its exit from the body.
└ 6th. Of the sympathies of heat, and of sympathetic heat.

SECOND CLASS.—FUNCTIONS RELATIVE TO THE SPECIES.

A COMPARISON OF THE TWO SEXES. HERMAPHRODISM.

ORDER FIRST.—_Functions peculiar to the male. Phenomena of puberty in
man._

GENUS I. _Production of the semen._
┌1st. Secretion in the testicle.
│2d. Residence in the vesiculæ.
│3d. Excretion Of erection and its phenomena.
│4th. Of the semen.
└5th. Of eunuchs.

ORDER SECOND.—_Functions peculiar to the female. Phenomena of puberty
in woman._

GENUS I. _Menstruation._
┌1st. Of its seat.
│2d. Of its periodical return.
│3d. Of its alterations.
└4th. Of its cessation.

GENUS II. _Production of milk._
┌Difference of this secretion from others.
┌1st. Secretion in the breast └Relation between the breast and womb.
│
│ ┌spontaneous.
│2d. Excretion └by suckling.
└3d. Of the milk.

GENUS III. _Of the fluids of women proper for generation._
┌What these fluids are.
└What is their influence.

ORDER THIRD.—_Functions relative to the union of the sexes, and the
product of this union._

GENUS I. _Generation._
┌1st. Sexual intercourse.
│ ┌Its phenomena ┌in the womb.
└2d. Conception │ └in the tubes and ovaries.
└Hypotheses.

GENUS II. _Gestation, relative_
┌1st. to the mother ┌General state of her functions.
│ └State of the womb.
│ ┌Of its animal life; it is almost nothing.
│ │Of its organic life ┌Functions that it wants.
└ 2d. to the fœtus │ └Activity of assimilation.
└Of monsters.

GENUS III. _Parturition and subsequent phenomena_
┌1st. Causes and mechanism of parturition.
│2d. Of the lochia.
│ ┌Development of its animal life.
└3d. Phenomena of the new born infant └Functions added to its organic.

This is a sketch of the general plan that I have adopted in my lectures. Those who have attended them, will find here some changes in one part, and additions in another. But they can easily arrange under it all the facts that are contained in this work, if they wish to refer them to a physiological classification, instead of distributing them according to the anatomical order in which I present them here.

Though a line of demarcation separates each order of functions, it is not necessary, however, to take, in too exact a sense, the divisions pointed out above. Each order is connected with the others, more or less intimately. For example, in the first class, when one order ceases, another is soon annihilated. It is thus that I have shewn elsewhere that the heart, which is the principal agent of organic life, being interrupted, the brain, which is the central organ of animal life, is immediately stopt for the want of excitement, and the functions over which it presides are destroyed. It is thus also, as I have shown, that the brain, having under its immediate superintendence, respiration, by the means of the diaphragm and intercostals, which receive the cerebral nerves, has the circulation directly under its control, and thus the whole of organic life, which ceases when its action is interrupted. It is on this account that I have considered respiration as the link that connects animal with organic life, and have proved that a fœtus without a brain, or without something to supply its place, cannot live out of the womb of its mother. Every thing is connected, every thing is united in the animal economy. We live without and within in a distinct manner, but one life cannot be preserved as a whole, independent of the other. Thus, though the functions should be studied abstractedly, we should always have in view their connexion, when we consider the whole of them as simultaneously in operation.

It will be seen that in the Descriptive Anatomy, I have adopted a classification analogous to that of physiology. The one differs, however, a little from the other, because the same organs often serve for many functions, and especially because certain functions, such as exhalation, nutrition, calorification, have not, to speak correctly, any distinct and determinate organs.

GENERAL ANATOMY.

SYSTEMS

COMMON TO ALL THE APPARATUS.

GENERAL OBSERVATIONS.

The organized systems of the living economy may be divided into two great classes. One, generally distributed and every where present, concurs not only in the formation of all the apparatus, but even in that of the other systems, and offers to every organized part a common and uniform base; this includes the cellular, arterial, venous, exhalant, absorbent, and nervous systems. The other, on the contrary, placed in certain determinate apparatus, foreign to the rest of the economy, has a less general and oftentimes an almost insulated existence; this embraces the osseous, cartilaginous, fibrous, muscular, mucous, serous systems, &c. &c.

The first part of this work will be devoted to the examination of the general systems, of the generative systems, if I may so express myself, systems which are not however of such importance that all the organized parts are necessarily provided with these six. In fine, in some there are neither arteries nor veins; in others nerves; in some but little cellular texture; but they concur to form the greatest number, and some are always found where others are wanting. Thus in the tendons, in the cartilages, &c. which are deprived of blood, there are exhalants, absorbents, &c.

In general, it appears that the exhalant and absorbent systems are the most universally diffused. Nutrition supposes this; in fact this function is the result of a double movement; one of composition, which brings to the organs, the other of decomposition, that carries from them the nutritive matter; now the exhalants are the agents of the first movement, and the absorbents of the second. As every organ is nourished, and as the mechanism of nutrition is uniform, it follows that these two systems belong to all the organs. After them the cellular system is the most generally found. Where there are no blood vessels, it is sometimes met with, and it always exists where these vessels are. Next to this, the arteries and veins are spread to the greatest number of parts. Oftentimes no nerve is discoverable, where they penetrate, as in the aponeuroses, the fibrous membranes, &c. &c. The nervous is of all the generative systems, that which is found by dissection in the smallest number of parts. The serous membranes, the whole fibrous system, the cartilaginous, the fibro-cartilaginous, the osseous, &c. appear to be deprived of it.

Particularly destined to form a part of the structure of other organs, the generative systems perform the same office for one another; thus the cellular texture enters into the composition of the nerves, and the arteries and veins; and the arteries and veins are ramified in the cellular texture, &c. It is a general intermixture of one with the other.

It may be imagined, from what has now been said, that the generative systems, considered under the relation of organs, forming a common and uniform base for all, ought to be sooner developed than others; and this, observation proves. While there is hardly an outline of the others in the first months of the fœtus, these predominate in a remarkable manner. The nerves, and their centre, which is the brain, the arteries, the veins and their central organ, which is the heart, the cellular texture, the exhalants and the absorbents, exhibit this phenomenon in a striking degree. Mere inspection suffices to prove this in the nervous, arterial, venous and cellular systems; in the other two it is proved by the wonderful activity of absorption and exhalation, at this period of life.

From what has just been said of the general systems of the economy, it is easy to perceive that they perform the most important part of nutrition. They form the nutritive parenchyma of each organ; now I call the nutritive parenchyma, the cellular, vascular and nervous outline of that organ. It is in this outline that the nutritive matter is deposited. This matter being different for each organ, establishes a difference between them. For the bones, it is phosphate of lime and gelatine; it is gelatine alone for the cartilages, tendons, &c.; fibrin for the muscles, albumen for certain other organs; so that if the nutritive parenchyma of a bone was filled with fibrin, it would be a muscle in the form of a bone, and vice versa, a muscle would become a bone with a muscular form, if its parenchyma was filled up with earthy and gelatinous substances. We should know the nature of all the living parts, if their nutritive substances were known to us; but the most of them are unknown, it is chemistry that must enlighten us upon this subject. All the organs resemble each other in their parenchyma, or at least have a great analogy. If it were possible to remove, from all the nutritive matter and leave this parenchyma untouched, we should see only among them, varieties of form, of size, of deposition of cellular layers, of vascular or nervous branches, but not of nature and composition.

In the first period after conception, the mucous mass that represents the fœtus, appears to be only a compound of the general systems. Each organ has as yet only its nutritive parenchyma, the parenchyma upon which nature has imprinted the form of the organ, that is to be developed there. In proportion as this outline is increased, the nutritive substances penetrate it, and then each organ, which until that time had been like the rest in its nature, and forming with them a homogeneous mass, begins to be distinct, and have a separate existence; each one draws from the blood the substance that is proper for it. This addition gives the attributes of thickness, of density, and of nature; but the increase of parenchyma, the augmentation of its dimensions are always antecedent to this. Whilst all inorganic bodies increase by the addition of particles, there is here at first an expansive force, from which length and breadth arise, afterwards substances are exhaled into the parenchyma, which lengthen and widen it.

By what mechanism is it, that each organ draws the materials of its nutrition from the blood, the common source? This depends entirely upon the organic sensibility peculiar to each, which places it in relation to this or that substance and not to another, and which makes it appropriate it to itself, is penetrated by it, and suffers it to enter its vessels on all sides while it draws back and contracts, to prevent what is foreign to it, from being introduced into its texture.

After this substance has continued for some time to form the organ, it then becomes foreign to it and heterogeneous; by remaining longer it would be injurious; it is absorbed and thrown out by the different emunctories; a new substance of the same kind, which is brought by exhalation, takes its place. Each organ is then constantly in a state of composition and decomposition; but this composition and decomposition vary in their proportion. The predominance of the first over the second, constitutes growth. Their equilibrium establishes the stationary state of the body, which is the case with the adult. When the activity of the second is greater than that of the first, then decrease and decrepitude follow.

Such is, in short, the manner in which the general theory of nutrition should be considered, a theory which I shall explain at length in my physiology, and upon which I will now offer a few words, to show that it is not a system formed by accident, but that it rests upon the laws of the economy, and upon its organic phenomena. Now I think that this assertion will be demonstrated, if I prove, 1st. the uniformity of the parenchyma of nutrition; 2d. the variety of the nutritive substances; 3d. the faculty which the parenchyma of nutrition has of appropriating to itself, according to the quantity of its organic sensibility, this or that nutritive substance, to the exclusion of others, of afterwards throwing out this substance, and of taking new. These are in fact the fundamental principles of this theory.

I say in the first place, that the parenchyma of nutrition is the same for all the organs, and that it is an assemblage of red vessels, of exhalants, of absorbents, of cellular texture, and of nerves; these are the proofs. 1st. These different organs are met with in all the others, as I have observed before, anatomy shows them every where, between each fibre, each layer, each point, if I may so say; they are truly the common organs. 2d. When we take away from the organs their different nutritive substances, for example, from the bones the phosphate of lime by acid, and the gelatine by boiling, there is a residue which is evidently cellular and vascular. 3d. There is no doubt but that the mechanism of the union of divided parts is the same as that of their natural nutrition. Now in the healing of wounds, the parenchyma of nutrition is first developed, and is every where the same; every where fleshy points appear, which are cellular and vascular, which have the same appearance and same character, whether they arise from a bone or a cartilage, a muscle, the skin, a ligament, &c. All wounds, in healing, like the organs, resemble each other in their parenchyma; they differ also like the organs, in the nutritive substance that is afterwards deposited in its texture, substances which vary according to the part where the wound happens to be; thus the deposit of the phosphate of lime gives to the callus a different character from that of muscular wounds, which are united by the exhalation of fibrin in the fleshy points that first arise upon the divided surfaces, &c. 4th. The mucous substance which forms the body of the embryo, appears to be nothing but cellular or mucous texture, as Bordeu calls it, which is abundantly supplied with vessels and nerves. In fact, when the organs are developed in this mucous substance, it may be seen in their interstices for a certain length of time, and exhibits there the same appearance as the body of the embryo in the first periods; gradually this substance becomes condensed, is filled with cells, and assumes the form of cellular texture; whence it may be presumed, that in this mucous state of the embryo, there is only the nutritive parenchyma of the organs; and as the parenchyma is the same in all, it is evident that the mass of the embryo must be homogeneous. Nutrition commences, and then each organ appropriates to itself the substance which is proper for it; after this it ceases to be homogeneous. From these considerations, it becomes easy to admit the uniformity of the parenchyma of nutrition, and its cellular, vascular and, in certain cases, nervous texture.

I am aware, that by admitting this common parenchyma of nutrition, it becomes necessary that it should be nourished itself, and consequently that we must go farther back; but in physiology, the art of finding the truth consists, in searching for it in secondary causes; here facts and experiments enlighten our way, beyond that, imagination only is our guide.

After having demonstrated that the organs resemble each other in a common parenchyma of nutrition, it is unnecessary to prove that they differ by the substances that are deposited there. Animal chemistry has within a few years past so much elucidated this point, that it is not worth while to waste time in refuting what has been written upon the identity of the nutritive juice.

In fine, it is easy to conceive, how each parenchyma of nutrition appropriates to itself according to the quantity of organic sensibility it enjoys, the nutritive substances that are proper for it, and which are brought to it by the circulation. It is not a phenomenon peculiar to nutrition; it is observable in all the acts of the organic economy. Thus the secretions take place only in consequence of the determined quantity of this sensibility, which, placing each gland in relation with the fluid that it should separate, makes it receive this fluid, and reject the others; thus the red part of the blood does not ordinarily pass into the exhalants, because the serous part is alone in relation with their organic sensibility; thus the substances that pass the intestines, do not stop in the biliary or pancreatic ducts, although their diameter is sufficient to admit them; thus cantharides are exclusively in relation with the sensibility of the kidneys, mercury with that of the salivary organs, &c. &c.

We see from this, that the mechanism by which the parenchymas of nutrition appropriate to themselves nutritive substances, is not an insulated phenomenon, but a consequence of a general law of organic sensibility. But why has this property as many degrees as there are organs in the economy? Why do these degrees establish relations so different between the organs and the substances that are foreign to them? Let us stop here; let us be contented with proving this fact by a great number of examples, without trying to discover the cause. We could offer nothing but conjectures upon this subject.

These few notions upon the nutritive phenomena, though indirectly connected with the subject of this volume, are not misplaced here; because in these phenomena, the generative systems upon which we are going to treat, perform the greatest part, and because we shall frequently have occasion to refer to them in the examination of the development of the organs, the development that authors have only vaguely examined, upon which the most exact and the most judicious of all physiologists, Haller, has only slightly glanced, but which however ought to receive the particular attention of physicians, of those especially who wish to consider diseases under the essential relation of the influence that age has upon them.

CELLULAR SYSTEM.

This system, which many know still, under the name of the cribriform body, the mucous texture, &c. is an assemblage of filaments, and of white soft layers, intermixed and interwoven in different ways, leaving between them spaces communicating together, more or less irregular, and which serve as a reservoir for the fat and serum. Placed around the organs, the different parts of this system act at the same time as a bond to connect, and as an intermediate body to separate them. Carried into the interior of these same organs, they essentially contribute to their structure.

The great extent of this system, which, though every where spread, is every where continuous, the number of organs it surrounds, and the multiplied relations it presents, do not allow me to describe it, as has been done, in one point of view; in order to give a complete view, it is necessary to separate the different points in which it may be examined.

I shall then at first consider abstractedly the general system, as represented by the continuity of all its parts, in order to consider it in relation to the organs that it surrounds, or to whose composition it concurs. I shall examine it afterwards independently of these organs, as it is spread everywhere in the spaces between them. In fine, its organization, its properties, its relations with other systems, and its development will be the object of my researches.

ARTICLE FIRST.

OF THE CELLULAR SYSTEM CONSIDERED IN RELATION TO THE OTHER ORGANS.

The cellular system, considered in an insulated manner, and in relation to each organ of the animal economy, can be described in two secondary relations. 1st. It forms for each organ a covering, a boundary which is exterior to it. 2d. It enters essentially into the structure of each, and forms one of the essential bases of this structure.

1st. _Of the cellular system upon the exterior of each organ._

The different conformation of the different organs, establishes two very distinct modifications in the relations of the cellular texture, that is exterior to them. In one case in fact, it is contiguous only to one of their surfaces, in the other it envelopes them entirely. The first arrangement takes place, when these organs have one side free, and the other attached, as for example, the skin. The second, which is the most general, is observed, when an organ is attached every where to those in the vicinity of it. Let us describe separately each of these two arrangements.

_Of the cellular system which adheres only to one side of the organs._

There are three membranous organs which are free on one side, and clothed on the other by the cellular texture; these are the skin, and the serous and mucous membranes. We can also consider here, that which covers the exterior of the arteries, the veins, the absorbents and the excretories, which are destitute of it in their interior. As this texture enters also into the structure of these vessels, most authors have examined it, in treating of them. It appears to me more convenient to present under one point of view all the parts of the cellular system.

_Sub-cutaneous cellular texture._

Besides the chorion, into which, as we shall see, a great quantity of cellular texture enters, and which anatomists consider as formed by a particular condensation of this texture, the skin, everywhere that we examine it, presents a subjacent cellular layer, the quantity and density of which vary in the different parts of the body.

Upon the greatest part of the median line, this texture appears more compact, and more adherent to the skin than in many other places. We may be convinced of this, by dissecting upon the middle of the nose, of the lips, of the sternum, upon the linea alba of the abdomen, upon the range of the vertebral and sacral spinous processes, upon the posterior cervical ligament, &c. From this adhesion arises a sort of division of the two great halves of the sub-cutaneous cellular texture; a division that I have sometimes made very evident in my experiments upon emphysema. The air being driven with moderate force under the integuments of one side of the body, diffuses itself gradually, and is stopped in many instances at the median line, so that one side is puffed up and the other exhibits the ordinary state of the cells. It is oftentimes necessary to increase the force very much, in order to overcome the resistance and render the emphysema general. However, we cannot always produce this phenomenon, and sometimes the air spreads immediately every where; this takes place especially if it is forced in about the neck, for the sub-cutaneous texture is as loose there in front, upon the median line, as it is upon the sides.

It is only from the circumstance, that the sub-cutaneous texture immediately under the median line, is somewhat more compact than elsewhere, that we can say with Bordeu, that this texture divides the body perpendicularly into two equal parts. No where, but under the skin, do we see any trace of this separation. Besides, I have demonstrated in one of my works, that the division of the body into two symmetrical parts, is a general attribute of the organs of animal life, an attribute which distinguishes them from those of the internal life, which seem to be characterized by their irregularity; it is under this relation, and not under that of Bordeu, which is contrary to anatomical facts, that the median line should be described.

In the other parts of the body, the sub-cutaneous cellular texture varies considerably. 1st. The density of this texture is remarkable in the hairy scalp, which is with difficulty separated on that account from the aponeuroses and subjacent muscles. Those who have often examined patients who have died of apoplexy, know that sometimes their heads and necks are emphysematous; I have already seen four. Now whilst considerable air is found in the face, little or none is met with under the hairy scalp. 2d. In the face, the sub-cutaneous texture is remarkably loose, it is very abundant there. 3d. Upon the trunk this laxity is also very evident; it accommodates itself to the motions which the great and broad muscles perform there. 4th. Upon the extremities, the sub-cutaneous cellular texture, situated between the aponeuroses and the skin, offers almost every where an equal degree of relaxation. It is only upon the palm of the hand and the sole of the foot that, its texture becoming more compact, the adhesion of the aponeuroses to the skin is more evident, an arrangement that is favourable to the use of these two parts, which are designed to adapt themselves to the forms of external bodies, to grasp and hold them. It is to this compact texture, that must be referred the difficulty that exists of making these parts subject to dropsical effusions. Long after every other part of the sub-cutaneous texture is infiltrated, this preserves its ordinary state. I have seen two patients affected with elephantiasis, where every part of the skin and subjacent texture of the lower extremities was enormously swelled, except the sole of the foot. The contrast of this part, remaining in its natural state, with the top of the foot, which was raised to an enormous swelling, gave that peculiar appearance that all authors have noticed. At the place of the annular ligaments, the sub-cutaneous cellular texture is very compact, and the adhesion of the skin, is also very evident; hence those contractions that are seen in the limbs of infants at the place of the ligaments, the fat penetrating but very little into the cells, that are very closely drawn together.

The sub-cutaneous cellular texture has several different uses. It furnishes the skin with the great mobility it enjoys, a mobility that is particularly observable in the great motions of the trunk and extremities, in the collisions it experiences with external bodies, in the different tumours that get to a great size, as in sarcocele, which is often covered at the expense of a part of the integuments of the penis, the abdomen and the thigh, which are stretched and have a real locomotion.

It is to this texture also, that the organs subjacent to the skin owe in part the facility with which they move in the great contractions of which they are susceptible. The fat contained in great quantity in its cells, contributes to protect the subjacent parts from the impression of the external air. We know, that in general this fluid is more abundant there in winter than in summer, that it is found in a very considerable proportion under the skin of animals that inhabit cold countries, that in consequence of the emaciation that follows great diseases, the impression of the external air is often very sensible, &c.

The serum appears to be in the sub-cutaneous texture, considerably more than in other parts; it has a greater tendency to accumulate there, no doubt on account of its laxity. If we compare the quantity of fluid which enters this texture in a dropsical limb, with that which occupies the intervals between the muscles and the interstices of the fibres of the different subjacent organs, we shall see that it exceeds it considerably, and that the size of the limb is in proportion much more increased by the dilatation of the portion of sub-cutaneous cellular texture, than by that of the portions situated deeper. To be convinced of this, place at the side of a healthy, lower limb, stripped of its integuments and subjacent texture, a dropsical limb prepared in the same manner, and consequently having like the other, only its aponeurotic covering, you will see that the difference is not very great.

_Sub-mucous cellular texture._

The mucous membranes have the same relations with the cellular texture, that the skin has, of which they are a continuation, and with which, as we shall see, they have a great analogy in their structure. There is then a sub-mucous, as well as a sub-cutaneous texture. But there is between them, this essential difference, that the texture of the first is infinitely more compact and condensed than that of the other, and consequently that the adhesion of the mucous system to the neighbouring parts is much greater, than that of the cutaneous system. It is to this difference that may be referred, 1st. the difficulty of dissecting the mucous membranes and of separating them from the subjacent parts. 2d. The impossibility that I have always found in many successive experiments, of producing an artificial emphysema in the sub-mucous texture, whilst I have done it almost every where else, by blowing in air. 3d. The uniform absence of this fluid in this texture, even when the natural emphysemas are the most generally spread. 4th. The equally uniform absence of serum in the sub-mucous cells, in the most general leucophlegmasia; a phenomenon essential to the functions of the hollow organs, which would soon be obliterated, if the sub-mucous texture swelled as much in dropsy as the sub-cutaneous.

Is it to the difference of texture of these two portions of the general cellular system, that must be referred the much greater frequency of phlegmonous inflammation in the second than in the first, or is it that this is less exposed to the exciting causes derived from external bodies? Both circumstances may have an effect. I believe much more readily in the first, as the throat, in which is seated, especially around the amygdalæ, the most lax of all the parts of the sub-mucous texture, is the most frequent seat of phlegmonous inflammation.

Besides, it is the firm and compact structure of the sub-mucous texture, which makes it fit to serve as a point of insertion and termination to that number of fleshy fibres that compose the muscular membranes of the stomach, the intestines, the bladder, &c. and thus to fulfil the uses that the tendons have in relation to the muscles of animal life.

_Sub-serous cellular texture._

There is under almost all the parts of the serous system, as under the two preceding ones, a cellular layer, which is in general very abundant and very loose, as we may be convinced by examining it around the peritoneum, the pleura, the tunica vaginalis, the pericardium, &c. This quantity of cellular texture is particularly destined to accommodate the different changes these membranes experience, in dilatation, in contraction, and in a species of locomotion, of which they are susceptible under many circumstances. We shall see the peritoneum, for example, belong at one time to the omentum, at another to the stomach, according as this last is in a state of fulness or vacuity; now for these removals, it was necessary that there should be a great degree of laxity in the surrounding texture. It is to this, that we must attribute the ease with which the sub-serous texture is penetrated with water in dropsies, and with air in emphysema. Next to the sub-cutaneous texture, no part is more disposed to these infiltrations.

There are, however, some places, where the serous membranes adhere in a very intimate manner to the neighbouring parts. The pericardium in its two layers, the synovial glands with the cartilages and fibrous capsules, the tunica arachnoides with the dura mater, offer examples of this arrangement, which constitutes, when it is with a fibrous membrane that it makes the adhesion, the sero-fibrous membranes.

_Cellular texture exterior to the arteries._

There is around each artery an extremely compact, condensed, and resisting layer, which at first sight appears to be a peculiar membrane, but which evidently belongs to the cellular system. It has the greatest analogy with that which is under the mucous membranes. It is never the seat of serous infiltrations. Fat never accumulates there, and it is never attacked with inflammation. It arises in an insensible manner from the neighbouring cellular texture, which is gradually condensed, and intermixed in such a manner, that we can detach it as a whole, so that it will represent a kind of canal corresponding with that of the artery which it surrounds and supports. Are the arterial fibres inserted in this compact texture, as the muscular fibres of the stomach and intestines are, in the sub-mucous texture? I do not think they are; for if it was the case, we could not so easily remove the cellular cylinder that surrounds the arteries; the arterial fibres seem to be whole circles, and consequently not to have, like the muscular, two inserted extremities. However, some of these fibres constantly adhere to the deepest cellular layer, when we remove it; we distinguish them by their direction and yellowish colour.

_Cellular texture exterior to the veins._

The veins have an external covering analogous to that of the arteries, but it is in general less thick and compact. It cannot be taken out in an entire cylinder as easily as that of the arteries. Moreover, it does not contain fat, and but little serum, and is not subject to dropsical effusions, but uniformly preserves in all affections its original state. When we raise by layers this texture which is on the outside of the coats of the veins, we easily perceive that it is dryer than in any other part; and I have often been tempted to believe, that it does not, like that of the arteries, the excretories, and mucous surfaces, exhale an albuminous fluid which lubricates the other parts of the cellular system. We shall see that its organization, which is entirely different, forms an exception in this system.

In examining the cellular cylinder of the veins and arteries, especially that of the first, it is essential not to confound it with their filaments, and the numerous nervous branches which come from the ganglions, and form a very thick net-work around them. The cellular texture is whiter, the nerves more greyish; this becomes very apparent after a few days maceration.

I do not speak of the texture external to the absorbents; without doubt they have one like the veins, but so delicate are these vessels, that we can say nothing of them founded upon experiment and dissection.

_Cellular texture exterior to the excretory ducts._

All the excretories, the salivary, urinary, spermatic, hepatic, pancreatic, &c. are evidently surrounded with a layer analogous to the preceding, entirely distinct from the neighbouring texture, and which appears to be inserted in it without partaking of its nature; it is a distinct body, as to its thickness, its form, and its texture. The filaments that compose it, not being separated in their interstices by any fluid, remain in contact with each other; so that the whole really makes a membrane in the form of a canal, which can be easily raised up like that which surrounds the arteries; it is, however, thicker than that of the veins.

_Of the cellular system considered in relation to the organs that it surrounds on all sides._

Except the organs of which we have just spoken, all parts of the body are surrounded on every side with a cellular layer more or less abundant, which forms for them, according to the happy expression of Bordeu, a kind of peculiar atmosphere, an atmosphere in the midst of which they are immersed, and which serves to insulate them from the other organs, to interrupt to a certain degree the communications which would unite them in an intimate manner, which would identify, if we may so say, the existence of one with the other, if they were in immediate apposition.

The serous vapour, in which the cellular atmosphere of each organ is constantly immersed, and the fat which floats there in greater or less abundance, powerfully assist in this insulation of vitality; both form for the different organs a line of separation, which, being fluid, enjoys in a much less degree than them the vital forces, which also in this point of view, is not at their level, if I may so express myself, and which is consequently very proper, to interrupt in a certain degree the vital communications that would otherwise exist. The essential difference that there is between the peculiar life of the cellular texture and that of the other organs, renders it also very susceptible of performing alone like a solid, an analogous use independent of the fluids it contains.

It is to this insulation of the vitality of the organs by their surrounding cellular texture, that we can refer in part that of the diseases, which is only an alteration of this vitality. Every day we see an affected part contiguous to a sound one, without communicating to it its disease. A healthy pleura covering the lungs filled with tubercles, or ulcers, in phthisis; an inflamed peritoneum corresponding with the intestines, the stomach, the liver, the spleen, which remain in their natural state; the mucous membranes affected with catarrhs approaching without danger the numerous parts they cover; the sub-cutaneous organs remaining free from the innumerable eruptions of which the skin is the seat; the tunica arachnoides in a state of suppuration enveloping a healthy brain, and a thousand other similar facts; these are the phenomena that the examination of bodies constantly presents. Shall I speak of the different tumours that are formed in the midst of organs, without their perceiving it, of the numerous excrescences that grow by their side without affecting them? Dissect a muscle under a suppurating cutaneous wound, or even a most obstinate ulcer; you will not often find it different from the rest, the skin only has been affected. No doubt the difference of vitality of two neighbouring organs is an essential cause of the insulation of their diseases; but the cellular atmosphere that protects them is also an important one. When an organ sends elongations into another, it communicates to it much more easily its diseases, than if a thick cellular layer separated them; for example, we know that the affections of the periosteum and the bone are soon identified.

Let us not, however, exaggerate this idea, by describing the cellular atmosphere as an insurmountable barrier to diseases. Facts would often contradict us, by showing diseases passing from an organ to the texture that surrounds it, and from this texture to the neighbouring organs; so that we see it at one time an obstacle, and at another the means of their propagation. The atmosphere that is formed is in different cases susceptible of being charged with all the emanations that arise from the organ, or to speak in language more strictly medical and physiological, the vital forces of an organ being altered, those of the surrounding texture are often altered by communication, and gradually those of the different neighbouring organs themselves. This kind of influence that the organs have upon each other, should be carefully distinguished from sympathy, in which, a part being diseased, another part becomes affected without the intermediate ones being deranged in their functions. Here there is constantly in the communication of diseases, the same order as in the position of the organs.

A great number of local affections affords us examples of this dependance, in which an organ and its texture being diseased, the neighbouring organs afterwards become so. In phlegmon, a more or less considerable swelling surrounds the red and inflamed place; rheumatism, which affects the white parts of the wrists and fingers, produces a painful swelling around them; a considerable tumefaction in the neighbourhood of the knee is almost always the result of diseases of the joint, which affect only the ligaments, &c. Many tumours have around them a kind of diseased atmosphere, an atmosphere which extends more or less remotely, which always exists in the cellular texture, and which constantly partakes of the nature of the tumour. If it is acute, as in phlegmon, it is a simple swelling which disappears almost entirely at death; as I have often seen in dead bodies an inflamed part that was very large during life, resume by the loss of the vital forces, nearly its ordinary size. Is the tumour chronic? it is an induration more or less evident that affects, oftentimes to a distance, the neighbourhood of the diseased parts, as we see in most cancers.

This atmosphere of disease is developed not only around the affected organ, but embraces also the neighbouring ones. The inflammations of the pleura spread to the lungs, that of the convex surface of the liver to the diaphragm; pericarditis, by the influence it has on the fleshy fibres of the heart, produces in this organ the irregular motions of an intermittent pulse; peritonitis, which is exclusively confined to the peritoneum, in the beginning, terminates, when it becomes chronic, by affecting the subjacent intestines; it is this which forms chronic enteritis, &c.

It should be remarked, however, that mere contiguity without cellular texture, is often sufficient to communicate disease; for example, a carious tooth affects its neighbour; the inflamed portion of a serous membrane, in contact with healthy ones, soon produces inflammation in them; thus it is, that after inflammation has continued a short time, though the pain has announced only one point to be primarily affected, the whole surface is found attacked.

I am convinced that disease is not the only thing, that the cellular atmosphere of the organs serves to propagate, but it is also the means of communicating medicinal effects. Why is a blister often useless that is applied to a remote part in rheumatism, whilst one placed upon the skin that covers the muscle or the fibrous organ that is the seat of the disease, frequently produces a sudden effect? Why has a cataplasm applied to the scrotum oftentimes an influence upon a diseased testicle, though between the cutaneous organ and this gland there is no relation of vitality? Why do several other medicines applied also to the skin, produce an action upon the subjacent parts? The cellular texture is certainly the means of communication, as in the different applications made to the mucous membranes. A gargle is advantageous in inflammations of the tonsils; an emollient enema diminishes that of the peritoneum, &c.: now these means are not applied directly to the affected organ; their effects are transmitted by the sub-mucous texture. However, the advantages of these applications have been much exaggerated, both when applied to the cutaneous and mucous surfaces, with a view of acting upon organs of different vitality, and which are subjacent to these surfaces. Practice too often proves that they may be excited, and irritated in a certain manner, without the contiguous organ being affected, because their life and that of the organ has no resemblance or correspondence, the one is indifferent to the affections of the other, though the parts are contiguous. Who does not know, how little effect emollients, discutients, &c. have, upon tumours of the breast, of the glands of the groin, axilla, &c.? and that they are as often cured without our applications as they are with? Formerly, when a tumour appeared projecting under the skin, if it was seated in the abdominal viscera, and consequently separated from the cutaneous organ, by many others of a different and even opposite vitality, they covered it with a poultice. All modern surgeons admit the inutility of applications made in this way, and now confine them to the most sub-cutaneous organs. Perhaps hereafter we shall be sufficiently acquainted with the degree of vitality of each organ, to know when the cellular texture can be the means of communication of medicinal effects, between two contiguous organs, with different structure and properties, and when it is a barrier which stops the communication of these effects. At present we go almost always groping in the dark.

Frequently a cutaneous application acts by sympathy upon very distant organs, whilst it has no effect upon neighbouring ones, with which it has no relation; for example, a bath will check a spasmodic vomiting, while it will have no sensible effect in diminishing pain which has its immediate seat in the sub-cutaneous organs.

In general, the vital forces of any organized part are particularly altered, and consequently its injuries are produced in three ways; 1st. by a direct irritation, as when the conjunctiva is inflamed, from fresh air, or that filled with irritating exhalations; 2d. by sympathy, as when one eye being affected, the other becomes so without any apparent cause; 3d. by cellular communication, as when a bone being carious, the skin that covers it becomes discoloured, livid and swelled.

Why is the cellular texture, in some cases, the means that nature uses to defend organs from the influence of that which is diseased, while in others it serves to propagate morbid affections? Let us limit ourselves upon this point to the exposition of facts; the research into the cause, would only be conjecture.

The cellular atmosphere of each organ has relation not only to the immediate phenomena of its vitality, but also to the different movements that the organ executes; as this is more abundant, these movements are more extended. This observation is made, in comparing that which is in considerable quantities around the heart, the great arterial trunks, the eye, the womb, the bladder, the great articulations, as the axilla, the groin, &c. with that which is on the outside of the tendons, the aponeuroses, the bones, &c. and of which there is in general only a very small quantity. The extension and contraction of which its cells are susceptible, make them very proper to accommodate the great movements of the organs, those especially of dilatation and contraction, which moreover are favoured by the fluids that it contains. The organs, upon the external surface of which but little cellular texture is found, and which, however, perform many movements, as the stomach, the intestines, the brain, &c. have, to supply its place, the serous membranes that cover them. These membranes and the cellular texture are in fact the two great means, and the only ones, by which nature has facilitated the movements of these organs.

There are many organized parts with obscure motions, but which are however surrounded with a quantity of cellular texture; the kidnies are a remarkable example of this. The testicle and its membranes are also surrounded with a great quantity of this texture; so is the thyroid gland; the pancreas and salivary glands find it a thick partition which separates them from the neighbouring organs. In general, almost all the immoveable parts, which are not of much importance, and which are not separated from others by serous surfaces, as are almost all the thoracic and abdominal viscera, are every where surrounded by an abundant cellular texture.

II. _Of the internal cellular system of each organ._

The cellular texture, after having covered the organs, enters every where into their intimate structure; it forms one of their principal elements. In an apparatus, which is an assemblage of many systems, each of these systems is united to the others by it; thus in the stomach, the intestines, the bladder, &c. different layers which belong to it separate the serous, muscular and mucous membranes of these different hollow organs. In the lungs, between the serous surface and the pulmonary parenchyma, between this and the divisions of the bronchia, between them and their mucous surfaces, it offers a variety of elongations more or less compact.