LYMPHATIC. A vessel containing lymph (q.v.), also called an absorbent, from the prop erty which it possesses of absorbing foreign mat ters into the system and carrying them into the circulation. The lymphatic system includes not only the lymphatic vessels and the glands through which they pass, hut also the lacteals which are nothing more than the lymphatics of the small intestine, and only differ from other lymphatics in conveying chyle (q.v.) instead of lymph during the latter part of the digestive process.
The lymphatics are minute, delicate, and trans parent vessels, of tolerable uniformity in size, and remarkable for their knotted appearance, which is due to the presence of numerous valves. for their frequent dichotomous divisions, and for their division into several branches before enter ing a gland. They collect the products of diges tion and the products of worn-out tissues, and convey them into the venous circulation near the heart. They are found in nearly every texture and organ of the body, excepting the substance of the brain and spinal cord, the eyeball, cartilage, tendon, and certain ftctal strictures, and possibly also the substance of bone.
The lymphatics are arranged in a superficial and a deep set. The superficial vessels on the surface of the body lie immediately beneath the skin, and join the deep lymphatics in certain points through perforations of the deep fascia; while in the interior of the body they lie in the submucous and subscrous a molar tissue. They arise in the form of a network, from which they pass to lymphatic glands or to a larger trunk. The
deep lymphatics are larger than the superficial, and accompany the deep blood-vessels; their mode of origin is not known with certainty. The structure of the lymphatics is similar to that of veins and arteries.
The lymphatic or absorbent glands are small, solid, glandular bodies, varying from the size of a hemp-seed to that of an almond, and situated in the course of the lyinphatic vessels. They are found in the neck (where they often become en larged and inflamed. especially in scrofulous sub jects), in the axilla. or armpit, in the groin (where, when inflamed, they give rise to the condition known as bubo), and in the ham; while deep ones are found abundantly in the abdomen and the chest.
The lymph of the left side of the trunk, of both legs, of the left arm, and the whole of the chyle is conveyed into the blood by the thoracic duet, while the lymph of the right side of the head, neck, and trunk, and of the right arm enters the circulation, at the junction of the axiIlary and internal jugular veins on the right side, by a short trunk, guarded at its opening by valves.
Among affections involving the lymphatic sys tem are inflammation of the lymph-glands in scrofula ; swelling of the lymph-glands in pul monary cancer, in tuberculosis, and in inflamma tion of the mouth and tongue; tumors involving the lymph-glands; lymphosarcoma, leucoey thwmia, etc.