_Neoplasms_.--Decannulation in neoplastic cases depends upon the nature of the growth, and its curability. Cicatricial contraction following operative removal of malignant growths is best treated by intubational dilatation, provided recurrence has been ruled out. The stenosis produced by benign tumors is usually relieved by their removal. _Papillomata_.--Decannulation after tracheotomy done for papillomata should be deferred at least 6 months after the discontinuance of recurrence. Not uncommonly the operative treatment of the growths has been so mistakenly radical as to result in cicatricial or ankylotic stenoses which require their appropriate treatments. It is the author's opinion that recurrent papillomata constitute a benign self-limited disease and are best treated by repeated superficial removals, leaving the underlying normal structures uninjured. This method will yield ultimately a perfect voice and will avoid the unfortunate complications of cicatricial hypertrophic and ankylotic stenosis. _Compression Stenosis of the Trachea_.--Decannulation in these cases can only follow the removal of the compressive mass, which may be thymic, neoplastic, hypertrophic or inflammatory. Glandular disease may be of the Hodgkins' type. Thymic compression yields readily to radium and the roentgenray, and the tuberculous and leukemic adenitides are sometimes favorably influenced by the same agents. Surgery will relieve the compression of struma and benign neoplasms, and may be indicated in certain neoplasms of malignant origin. The possible coexistence of laryngeal paralysis with tracheal compression is frequently overlooked by the surgeon. Monolateral or bilateral paralysis of the larynx is by no means an uncommon postoperative sequel to thyroidectomy, even though the recurrent nerves have been in no way injured at operation. Probably a localized neuritis, a cicatricial traction, or inclusion of a nerve trunk accounts for most of these cases. _Hyperplastic and cicatricial chronic stenoses_ preventing decannulation may be classified etiologically as follows: 1. Tuberculosis 2. Lues 3. Scleroma 4. Acute infectious diseases (a) Diphtheria (b) Typhoid fever (c) Scarlet fever (d) Measles (e) Pertussis 5. Decubitus (a) Cannular (b) Tubal 6. Trauma (a) Tracheotomic (b) Intubational (c) Operative (d) Suicidal and homicidal (e) Accidental (by foreign bodies, external violence, bullets, etc.) Most of the organic stenoses, other than the paralytic and neoplastic forms, are the result of inflammation, often with ulceration and secondary changes in the cartilages or the soft tissues.