ANATOMY AND PHYSIOLOGY OF THE GLANDS.
In ordinary language a “gland” means a gland of the lymphatic system. It is in this sense that I use the term in the present treatise. Anatomically speaking, all the organs of the body which secrete definite fluids, such as the liver, the kidneys, the salivary glands, the sweat and sebaceous glands of the skin, and also some organs which have no known secretion, as the pineal and thyroid bodies, are glands. But when the word gland is used absolutely, it is the lymphatic glands which are understood to be meant.
The lymphatic glands are little bodies varying in size from a lentil to an almond, and are very widely distributed over the body. They are like so many “locks” on the system of lymph canals, which form a network of vessels spread over the whole of the soft tissues. The office of these vessels is to take up the used-up materials of the body, pass them on to the lymphatic glands, which so act on them as to make them again fit to be poured into the current of the blood.
In the ordinary course of events the glands are very well able to discharge their functions, but at times extra pressure is put upon them. When one has a gathered finger, instead of the ordinary amount of waste products of the part, there is a great increase, and some of them are of a highly irritating character. In consequence of this we often find a red streak running up the arm from the injured finger to the armpit, and in the armpit one or more enlarged and painful glands. This means that the irritating matters are being dealt with by the glands. These may prove equal to the strain put on them, or they may inflame and suppurate themselves.
On dissection the lymphatic glands are found to consist of a capsule, and an internal portion composed of pouches communicating with each other, and richly supplied with blood- vessels and nerves. The pouches contain “a molecular fluid in which numerous nuclei and a few cells may be found in all stages of development”-(Bennett). There are lymphatic vessels leading into the glands and others leading away from the glands. The lymphatic vessels are provided with valves which only permit the fluid they contain to travel in one direction, away from the surface in the direction of the heart. Those vessels which enter a gland open into the lymph spaces of the outer portion of the gland; those which leave it are connected with the internal portion.
The distribution of the glands is very extensive. The chief localities in which they are found are the neck, the armpits, and the groins externally, and internally under the lining membrane of the abdominal cavity (peritoneum), and in the folds of it, where it forms the band of attachment for the bowels (mesentery), and in the chest along the larger bronchial tubes, at the root of the lungs, and at the base of the heart.
It will easily be understood that the function of this system of glands and vessels is of very great importance. The apparently solid tissues of the body are in a constant state of flux, of building up and of decay, and on the regular discharge of this process of interchange (metabolism, the scientific call it) the health of the body depends.
It is one function of the lymphatics to take up the waste materials of the tissue and re-organize them, so far as they are capable of it, for the rebuilding of the same or other tissues. If they act too sluggishly the tissues become thick and unhealthy, and a state of obesity, either local or general, may result; if they act too energetically the opposite condition of wasting will ensue.
But they have another function of enormous importance in the economy. I have spoken of the familiar instance of glands inflaming in the armpit when there is inflammation of some part of the arm or hand.
The lymphatics, therefore, not only deal with the waste of the body, they attack the products of diseased action, and, so far as they can, destroy the virus of disease.
I will not rest content with my own authority on this point. The Lancet of May 12, 1894, reports a discussion on a paper by Dr. Walter Carr, entitled. “The Starting-points of Tubercular Disease in Children.” In the report of the discussion which followed I find the following:-
“Dr. Routh pointed out the value of the lymphatic glands as a means of arresting the disease, in the same way that the poison of syphilis or of a dissection wound was arrested.”
“Dr. Carr, in reply, said… he believed that the glands were usually infected near the primary source of infection. He had no doubt that the lymphatic glands did act as filters and arrested the disease.”