Diseases of the larynx more especially involve the mucous membrane by which it is lined. Of these the more common are: (1) Laryngitis or inflammation; (2) ulceration; (3) oedema or effusive swelling. In addition, it is also liable to disorder of the nerves, by which its movements are regulated. These neurotic disturbances are represented by (a) paralysis, (b) spasm. Morbid growths, in the form of tumours or polypi, are also now and again accountable for laryngeal trouble.