Part 21

The glandular texture is distinct from most of the others in this, that the fibrous arrangement is wholly foreign to it. The elements that compose it are not placed at the side of each other, in longitudinal or oblique lines, as in the muscles, the fibrous bodies, the bones, the nerves, &c. They are found agglomerated, united by cellular texture, and adhere but very slightly. Thus whilst the organs with distinct fibres resist much, especially in the direction of their fibres, these are torn with the least effort, and break even with ease. Their rupture is unequal, full of prominences and depressions, a difference which distinguishes them from cartilage, the rupture of which is in general smooth. This rupture is not equally easy in all the glands. The prostate, the amygdalæ, the mucous glands resist much more than the liver or the kidneys, which principally exhibit this phenomenon. The pancreas and salivary glands yield a little without breaking, when they are pulled; but it is not their texture which is the seat of this phenomenon, it is the abundant cellular texture that penetrates them; thus their different lobes are then separated, in proportion as the filaments which are between them become longer.

The glandular texture, which is very commonly called parenchyma, is in general arranged in three different ways. 1st. In the pancreas, the salivary and lachrymal glands, there are distinct lobes, separated by cellular texture, resulting from smaller lobes which are agglomerated together and which are composed of still less lobes, that are called glandular grains; the scalpel traces with ease the first, second, third and even fourth divisions. 2d. In the liver and the kidneys there is found no trace of the first of these divisions, of those into principal and even secondary lobes. The glandular grains all in juxta-position, having between them an equal quantity of cellular texture, a quantity which is very small, as we shall see, present an uniform texture without inequality, which is broken with ease, as I have said, and the rupture of which exhibits species of granulations. 3d. The prostate, the amygdalæ and all the mucous glands have a soft parenchyma, like pulp, without the appearance of principal or secondary lobes, or even glandular grains, not breaking, yielding much more under the finger that compresses it, than that of the other glands. The simple inspection of the glandular system is sufficient to enable any one to perceive the triple difference which I have just pointed out, and which is essential. The testicles and the mammæ have a peculiar texture which cannot be referred to these differences.

Authors have been much occupied with the intimate structure of the glands. Malpighi admitted that there were small bodies in them, which he believed were formed of a peculiar nature. Ruysch determined that they were all vascular. Let us neglect all these idle questions, in which neither inspection nor experiment can guide us. Let us begin to study anatomy where the organs can be subjected to our senses. The exact progress of the sciences in this age is not accommodated to all these hypotheses, which made general anatomy and physiology but a frivolous romance in the last.

There is no doubt that the excretories communicate with the arteries which penetrate the glands. Injections made in these escape with great ease by the first, without there being any trace of extravasation in the gland. The blood flows often naturally by the excretories, and produces sometimes bloody urine, saliva, &c. But do these facts prove that there are only vessels in the glands, that the peculiar parenchyma of which they are the result does not depend on a substance which is peculiar to them? The glands, like all the other organs, as the muscles, the bones, the mucous membranes, &c. have their peculiar texture which especially characterizes them, which belongs only to them, a texture in which the arteries communicate with the veins and the excretories. Let us not push our researches further; if we do, we shall be inevitably entangled in conjectures. Let us confine ourselves to examining what phenomena distinguish this texture from all the others when subjected to the different reagents. It is much to know the characteristic attributes of the glandular system, without seeking to understand its intimate nature, which, like that of all the other systems, is concealed by an impenetrable veil.

The glandular parenchyma dried in the air after having been cut in slices, loses its original colour, takes a deep one, black even in the liver and the kidneys, in which it is owing especially to the blood which penetrates these glands, since if they are dried after having been deprived of it by repeated washing, they remain grey after their drying. No system becomes harder or more brittle than this by this preparation. It diminishes then less in size than most of the others. When immersed in water after being thus dried, it becomes soft, resumes in part its original appearance and its tendency to putrefaction, which takes place immediately if it is left in the open air.

The glandular texture, when exposed to the air so that it does not dry, becomes putrid very quickly, and gives out an odour more fetid than most of the others. More ammonia appears to be disengaged from it. The liver especially produces an insupportable odour when putrid. I do not know any organ, kept in a vessel full of water to macerate, which gives out more disagreeable emanations. The kidney becomes putrid much less quickly; this varies however a little.

When boiled, the glandular texture furnishes in the first moments of ebullition, a great quantity of grey substance, which mixes at first perfectly with the water which it renders turbid and then collects into a copious scum on the top of this fluid. It is this texture, the fleshy, the mucous and the cellular which give the most scum in boiling, as it is the cartilaginous, the tendinous, the aponeurotic, the fibro-cartilaginous, &c. which give the least of it. It should not be believed, moreover, that this first product of stewing is uniform in its nature; it varies in each system in quality as well as quantity. At least I have observed that its appearance is never the same, that it has nothing constant but its frothy state, which also varies much and which is even almost always nothing in the mucous system.

The liquor which results from the boiling is very much changed in colour, and appears to contain many more principles than that made with the white organs. An accurate analysis of the liquor in which each system had been boiled would be an interesting subject of research. I have found that in almost all the appearance, the taste and the colour were different.

The glands exhibit a phenomenon when cooking that especially distinguishes them. They harden at the moment of the first ebullition, and acquire the horny hardness like all the other systems; but whilst most of these soften again from long-continued stewing, so as to become pulpy, the glands uniformly become harder, so that after five or six hours boiling, they are three or four times as hard as they naturally are. I have very often made this experiment, which is also well known in our kitchens, in which when a gland is cooked, care is taken that the stewing should not continue too long. Beef kidney finally becomes soft; those of sheep and of man remain hard for a much longer time. They soften however more than the texture of the liver, which is of all the glands that which exhibits the hardness in the greatest degree.

Another phenomenon which especially distinguishes the ebullition of the glandular system, is that when it is taken out at the moment it has undergone the sudden horny hardening, common to almost all the animal solids plunged into boiling water, it has not like the others acquired elasticity. Draw in an opposite direction a tendon, a serous or mucous membrane or a muscle that have undergone the horny hardening, they stretch and afterwards suddenly contract the instant the extension ceases; on the contrary, a slice of liver that has the horny hardness breaks when it is drawn and never contracts. The texture of the prostate appears to be more capable of then acquiring a little elasticity. The non-fibrous disposition of the glands seems to have much influence upon this phenomenon.

Exposed to the sudden action of a very bright fire as in roasting, the texture of the liver and the other glands crisps and contracts on the exterior. There results from it on the surface a kind of covering impermeable in part to the juices contained in the organ, which in this way becomes cooked in these juices which soften it in the interior. This phenomenon is however common to all the solids. Hence why care is taken to expose what is roasting, whether it be muscular or glandular, at first to the action of a very quick fire; afterwards when the horny hardening of the surface has been produced, it is diminished, and the organ is cooked with a small fire.

The glands macerated in water yield differently to its action. The liver resists it longer than the kidney, which after an experiment of two months made in vessels placed in a cellar has been reduced to a reddish jelly swimming in the water; whilst the first preserved for the same time and a little longer, its form and density, and had only changed its red colour to a blueish brown, whereas the kidney retains its colour in maceration. The salivary glands contain much of this white, unctuous and hard substance, which all the cellular parts when long macerated exhibit. It is not the glandular texture that has changed, but only the fat contained in the cellular texture, which is here very abundant.

The acids act upon the glandular texture nearly the same as upon all the others. They reduce them to a pulp which varies in its colour and the rapidity of its formation, according to the acid employed. The sulphuric is uniformly the most efficacious in producing this pulp which it blackens, whilst the nitric yellows it. All the acids act with much more difficulty upon the glandular texture when stewed, than when raw. My experiments have convinced me that but few systems exhibit this difference in a more remarkable manner.

The glands are much less digestible than many other animal substances, especially when stewed, which produces in them in this respect an effect entirely different from what it does in the cartilages, the tendons, and all the fibrous organs, which by it lose their density, become soft, gelatinous, viscid even and are easier dissolved by the gastric juice. I believe in general that we should digest the glands much easier by eating them raw. Every one knows that the more the liver is cooked, the more indigestible it becomes. This induced me to make a comparative experiment upon this organ cooked and raw; when one portion in the second state was reduced to a pulp in the stomach of a dog, the other portion in the first state swallowed at the same time had just begun to be altered.

Of the Excretories, of their Origin, of their Divisions, &c. Of the Glandular Reservoirs.

All the glands have ducts destined to carry off the fluid which they secrete from the mass of blood; now as they are only found in the glands, they should be considered with the peculiar texture of these organs. The origin of these ducts is uniform in all the glands. They arise, like the veins, by an infinite number of capillaries, which form the last ramifications of a kind of tree, these ramifications appear to begin at each glandular grain, where these grains exist; so that for each there is one of these, an artery and a vein. Arising thus from the whole of the interior of the gland, these ducts soon unite and form larger ducts, which usually go in a straight line though the glandular texture, converge towards each other, unite with other ducts still larger and terminate differently.

In respect to this termination, glands should be divided into three classes. 1st. Some transmit their fluids by many ducts, each of which is the assemblage of smaller ducts, opening at the side of each other, but all entirely distinct and without communication. Sometimes at the place where these ducts terminate, a more or less considerable prominence is observed, as on the breast, as also on the prostate, of which the verumontanum is a kind of nipple. Sometimes there is a depression, a sort of cul-de-sac which is found at the place of these orifices, as in the amygdalæ, upon the tongue, &c. Sometimes the surface on which the different ducts of a gland open, is smooth and even, as is the case with that on which those of the lachrymal, sublingual and almost all the mucous glands open. 2d. Other glands pour out their fluid by a single duct, as the parotids, the pancreas, the sublinguals, &c.; this arrangement is only a modification of the preceding; where the duct opens, no inequality is usually discovered, the surface is smooth. 3d. There are glands which, before throwing out their fluid by their excretories, deposit it for some time in a reservoir where it remains to be afterwards expelled; such as the kidneys, the liver, the testicles, &c. Here there are always two excretories, one which goes from the gland to the reservoir, the other from the reservoir outwards. These reservoirs are evidently a part of the same system to which their excretory ducts belong.

Though the first and second species of glands have no reservoir, yet the different ramifications of their excretories may to a certain extent be considered as such. In fact, these ramifications, as well as those of the excretories of the glands with a reservoir, are constantly full of the fluid which is secreted in these organs. Whatever may have been the kind of death, the fluid of the prostate may be always made to ooze out, by compressing the gland; I have often even by pressure produced a very evident jet. The papillæ of the kidney also uniformly give out urine when pressed. The liver cut in slices allows natural bile to escape from the divisions of the hepatic duct. The semen is uniformly found in the windings of the vas deferens. The lactiferous vessels keep the milk in their cavity, till it is evacuated, and it has even no other reservoir. The greater or less size of the mammæ during lactation is owing to the greater or less fulness of these vessels. It is also to this circumstance that must be referred the peculiar taste of each glandular texture, which always borrows some sapid particles from the fluid it secretes. We know that the kidney has always an urinous odour, especially in old animals. It is to this also that I refer the difference of putrefaction which I have observed between this organ and the liver. We know that the bile undergoes putrid fermentation sooner than the urine; this, when it is very acid, can even preserve it to a certain extent from putrefaction; expose then the liver and the kidney to it, the latter will almost always be the last to become putrid, as I have said.

It appears in general that the course of the fluids in the excretories is much less rapid than that of the blood in the veins and even than that of the lymph in the absorbents; the following considerations place this beyond a doubt. The urine flows continually by the ureters, as is evidently proved by fistulas in the loins; now, in the time taken to fill the bladder by this uninterrupted flowing, there would flow from a vein of a diameter equal to that of the ureter ten times as much blood, and much more lymph from the thoracic duct. Yet this rapidity of motion is subject to many varieties; during the period of inactivity of the glands, it is not half as great as during their activity; the salivary fistulas are a proof of this. We know how promptly the ureters transmit the urine from the drinks that are taken.

Size, Direction and Termination of the Excretories.

The size of the excretories varies. 1st. Those which go out in considerable number from a gland are very small, often hardly perceptible. They commonly run their course in a straight line, do not anastomose with each other and open immediately upon going out of the gland. 2d. Those that are single are larger, always in proportion to the size of their gland, except however the hepatic which is evidently very small in comparison with the liver. They run their course out of their glands, and arise from ducts as large as those of the preceding ones; so that if a single trunk arose from the excretories of these, they would resemble the others in every respect. They differ only in this, that their secondary excretories open directly on their surface, whereas they unite in a common trunk in the others. The pancreas is the only one in which this common trunk goes concealed in the gland itself. It is only in the testicles that it is tortuous, and in which, on this account, it is longer than the course which it has to run.

Whatever may be their arrangement, the excretories pour all their fluid either on the exterior, as the urethra, and ureters, the lactiferous tubes, and the ducts of the sebaceous glands; or on the interior of the mucous membranes, as the mucous, salivary, pancreatic, prostate and hepatic excretories. The cutaneous and mucous surfaces are the only ones then on which the excretories terminate, the only ones which their fluids moisten. These ducts are never seen opening upon the serous or synovial surfaces. The excretories of the pretended articular glands would be, if they existed, an exception to the laws of the general organization. The excretories never open in the cellular texture; if this happens preternaturally, either abscesses take place from the irritation which results from it, as in urinary fistulas, or a callus forms in the course of the excreted fluid, and thus defend the cellular system from a troublesome infiltration.

Hence the mucous tube of the intestines should be considered as a kind of general excretory added to the pancreatic, hepatic excretories, &c. and which throws out all the fluids which are separately poured by these ducts into it. In fact, all the secreted fluids appear to be destined, as I have said, to be thrown out of the body. Separated from the mass of blood, they are foreign to it, and do not enter it in a natural state. Though still contained in cavities with mucous surfaces, they may be truly considered as being out of our parts. These surfaces are really true internal integuments, destined to defend the organs from the contact of the substances which they contain, a contact which would inevitably be injurious to them.

Remarks on the Secreted Fluids.

The fact that the secreted fluids are destined to be thrown out, a fact which is incontestable with regard to the urine, the bile which colours the excrements, the saliva, &c. has made me for a long time believe that the introduction of these fluids into the sanguineous system, would produce the most serious consequences. I was besides confirmed in this, 1st, by my experiments, in which I have always seen, as I have said, the urine, the bile, &c. injected into the cellular texture, remain without being absorbed, but producing abscesses; 2d, by the infiltration of the urine in the neighbourhood of the bladder, from which abscesses always arise; 3d, by the serious consequences from the effusions of this fluid in the peritoneum from the high operation for the stone, and of the bile on the same surface in certain penetrating wounds, in both these cases these fluids never re-enter the blood by way of absorption, like the peritoneal serum, but almost always occasion death; 4th, by an experiment in which I had seen a dog die shortly after the injection of urine into the jugular. All these considerations made me suspect that the secreted fluids, introduced again into the mass of blood, were always fatal at the end of some time, and that, as some physicians whose opinion is of great weight have thought, all that has been said of the bile’s being poured into the blood in bilious diseases, is but a consequence of vague ideas of the reality of which there is no proof. Yet the importance of this question, in regard to medical theories, has induced me to resolve it by experiments, so as to leave no doubt upon the subject.

I have then injected into the jugular veins of many dogs bile taken from the gall-bladder of other dogs which I opened at the same time. For the first few days they appeared to be weary, did not eat, were much altered, their eyes were heavy, and they were constantly lying down; but after some time they gradually regained their former vigour. I afterwards employed human bile in these experiments; the result was the same, except that many times, the animal had hiccough and vomiting some time after the injection. In one instance a dog died in three hours after the experiment; but it was because I made use of that extremely black fluid that is sometimes found in the gall-bladder instead of bile which resembles thick ink, and which appears to form a considerable part of those black vomitings that sometimes take place.

These experiments induced me to try some with the saliva, and I obtained the same result from them; only the languid state that succeeded the injection was less evident. I afterwards made use of nasal mucus suspended in a sufficient quantity of water, for it can hardly be dissolved in it. Finally urine itself was many times injected, not that which comes immediately from drink and is only aqueous, but that which is of slow formation. In this experiment the dogs have been sicker, but only one died, and that happened on the seventh day. I have many times repeated it, on account of that which I performed three years ago; the same result has always taken place, which makes me think that being but little used at that time to make experiments, I introduced by accident a bubble of air through the syringe, which is sufficient to produce the death of the animal.

A question then is evidently settled by the experiment. The secreted fluids, though destined to be thrown out in the natural state, can re-enter the circulation, without causing the death of the animal, which is only more or less affected according to the nature of the fluid injected. Whether the bile circulates or not with the blood in bilious fevers, I have not examined; but it certainly can circulate with it after having been absorbed in its canals. I do not doubt but that in purulent reabsorptions, the pus circulates in its natural state in the sanguineous system; I confess that I have not made experiments upon the injection of this fluid, but I intend to immediately.