This is a common result of repeated attacks of acute catarrh, but may occur spontaneously. It is chiefly characterized, like other chronic inflammations, by new-formation of tissue; the mucous membrane is thickened, and its surface is irregular. The increase is mainly of connective tissue which, having the usual characters of that resulting from inflammation, gives rigidity to the parts. The movable structures of the larynx are thus rendered more or less stiff, and hoarseness is the result. Not infrequently flat superficial ulcers or erosions form, and these have their seats most commonly at the posterior commissure. The racemose glands of the larynx may undergo special enlargement so as to appear as rounded prominences. They sometimes ulcerate, and so give rise to small crater-shaped ulcers, which are chiefly to be seen on the epiglottis and ary-epiglottic ligaments. The thickening and contraction of the connective tissue are sometimes so great as to produce very great Stenosis of the larynx, so that tracheotomy is needed to permit of respiration. Sometimes mucous polypi form on the surface, and add to the irregularity.