When one gland of a pair is wanting or becomes diseased, sometimes the other increases considerably in size, as I have seen in the kidneys. This takes place also in the treatment by compression of salivary fistulas, a treatment which does not however always succeed. In other cases, the sound gland increases its action and secretes more fluid, without increasing in size.
The exterior of the glands not covered by membranes is unequal and lobulated; it conforms to the muscles, the vessels, the nerves, and even the bones, as the parotid which is placed under the angle of the jaw. Less cellular texture is in general found around them, than around organs with great motion. That which is in contact with them is more dense and compact than that of the organic interstices. It closely resembles the sub-mucous texture, that exterior to the arteries, the veins, the excretories, &c. but it is not however so resisting. It receives fat with difficulty, and forms a kind of membrane, which, insulating to a certain extent the vitality of the gland, performs in great measure in this respect the functions of the peritoneum around the liver, of the peculiar membrane of the kidneys, the spleen, &c.
ARTICLE SECOND.
ORGANIZATION OF THE GLANDULAR SYSTEM.
I. Texture peculiar to the Organization of this System.
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.