The nature of these swellings is to be recognised by their situation, by their having existed from infancy, and, if necessary, by drawing off some of the contents of the cyst through a fine needle. They are usually remarkably indolent, persisting often for a long term of years without change, and, like the hæmangioma, they sometimes undergo spontaneous cicatrisation and cure. Sometimes the cystic tumour becomes infected and forms an abscess--another, although less desirable, method of cure. Those situated in the neck are most liable to suppurate, probably because of pyogenic organisms being brought to them by the lymphatics taking origin in the scalp, ear, or throat. If operative interference is called for, the cysts may be tapped and injected with iodine, or excised; the operation for removal may entail a considerable dissection amongst the deeper structures at the root of the neck, and should not be lightly undertaken; parts left behind may be induced to cicatrise by inserting a tube of radium and leaving it for a few days. Lymphangiomas are met with in the abdomen in the form of _omental cysts_. DISEASES OF LYMPH GLANDS #Lymphadenitis.#--Inflammation of lymph glands results from the advent of an irritant, usually bacterial or toxic, brought to the glands by the afferent lymph vessels. These vessels may share in the inflammation and be the seat of lymphangitis, or they may show no evidence of the passage of the noxa. It is exceptional for the irritant to reach the gland through the blood-stream. A strain or other form of trauma is sometimes blamed for the onset of lymphadenitis, especially in the glands of the groin (bubo), but it is usually possible to discover some source of pyogenic infection which is responsible for the mischief, or to obtain a history of some antecedent infection such as gonorrhœa. It is possible for gonococci to lie latent in the inguinal glands for long periods, and only give rise to lymphadenitis if the glands be subsequently subjected to injury. The glands most frequently affected are those in the neck, axilla, and groin. The characters of the lymphadenitis vary with the nature of the irritant. Sometimes it is mild and evanescent, as in the glandular enlargement in the neck which attends tonsillitis and other forms of sore throat. Sometimes it is more persistent, as in the enlargement that is associated with adenoids, hypertrophied tonsils, carious teeth, eczema of the scalp, and otorrhœa; and it is possible that this indolent enlargement predisposes to tuberculous infection. A similar enlargement is met with in the axilla in cases of chronic interstitial mastitis, and in the groin as a result of chronic irritation about the external genitals, such as balanitis.