Tuberculosis of the larynx is usually secondary to pulmonary phthisis, the mucous membrane being infected by the sputum from the lungs; it occurs in about 30 per cent, of the cases of tuberculosis of the lung. It is occar sionally primary. Even when the laryngeal tuberculosis is secondary to that of the lung, it may seriously aggravate the latter by the infective material from the ulcerated surfaces being carried into the lung by insufflation.

The author has recorded a case of primary tuberculosis of the larynx. On the other hand, from observation in several cases he is induced to believe that, not infrequently, a slight pulmonary tuberculosis produces an infection of the larynx, and that the latter may advance while the former retrogrades. The laryngeal phthisis may thus slowly go on to ulceration while the pulmonary affection heals. Subsequently the lung may become re-infected from the larynx. This is the explanation of the fact that in cases of ulcerated laryngeal tuberculosis, there is often a very rapid and extensive tuberculosis of the lung, which presents the features of an almost simultaneous infection.

In cases of phthisis pulmonalis the mucous membrane of the larynx is frequently pale from anaemia, but this may be nothing more than a manifestation of a general anaemia secondary to the wasting disease of the lungs. The first result of the actual tubercular disease is inflammatory thickening of the mucous membrane. There is at first chiefly an exudation of serous fluid and cellular infiltration so that it is mainly an (edematous thickening. It is most marked in the epiglottis and ary-epiglottic folds, these latter often showing themselves as rounded prominences. In this stage microscopic examination shows the presence of tubercles with their characteristic structure, along with the cellular condition of inflamed tissue. The tubercles are in the mucous membrane and the submucous tissue, the epithelium being.as yet intact.

To the thickening succeeds ulceration, the ulcers being at first small and superficial. These ulcers result from the caseation and softening of superficial tubercles. By coalescence larger ulcers form out of the smaller ones, and there is a continual tendency to spreading. As a rule there are many ulcers, and between them is thickened mucous membrane, which at the borders of the ulcers sometimes presents irregular projections like papillary outgrowths. The ulcers are at first superficial, but as the disease progresses considerable destruction of tissue may result. The vocal cords are not infrequently destroyed, and so there is loss of voice, but the voice may be lost from the rigidity of the structures caused by thickening from chronic inflammation. Again, perichondritis not infrequently follows, with suppuration, and this causes still further inflammatory manifestations.

Ulceration not uncommonly exists in the trachea and bronchi as well as in the larynx. There are many ulcers, and it is not uncommon to find the cartilaginous rings of the trachea extensively exposed. With these ulcerations of the trachea there is swelling of the mucous membrane around and sometimes a perichondritis with necrosis.

The lymphatic glands in the neck are affected secondarily to the larynx; they are the seat of tuberculosis as already described, and their enlargement may, in some cases, aid in the exact diagnosis of the disease in the larynx.

Leprosy produces in the larynx thickenings and ulcerations similar to those of the skin.

Glanders also attacks the larynx, producing the lesions already described.