This disease, which is not of very frequent occurrence, is an inflammation of the mucous membrane beneath the glottis. It may be acute at its onset, but it generally passes into a chronic stage. It has been observed as a sequel to erysipelas and typhus fever, and may take origin apparently in inflammation of the perichondrium. In acute cases there may be considerable oedematous swelling. In the chronic form there is thickening of the mucous membrane as in ordinary chronic laryngitis. The inflammation is often just beneath the cords, and so may produce fixation of them, but it may occur further down, and is not infrequently in patches interrupted by normal mucous membrane.