=Dangers.= With ordinary precautions no accident should occur, but the following may be mentioned: (1) if the furuncles are deeply placed, the tympanic membrane may be incised inadvertently, and a middle-ear suppuration may result; (2) a too violent incision may cut through the meatal cartilage posteriorly, and, as a result of septic infection, may give rise to perichondritis of the auricle. This, fortunately, is rare. REMOVAL OF EXOSTOSES FROM THE EXTERNAL MEATUS =Indications.= The indications vary, depending on whether there is a coexisting middle-ear suppuration or not. =If there be no middle-ear suppuration.= Operation is not urgent, but is justifiable under the following conditions:-- (i) _When one ear only is affected._ (_a_) If there be complete deafness due to obstruction of the auditory canal. The question of operation, however, should be decided by the patient, because it may be postponed indefinitely so long as no symptoms occur. (_b_) If there be recurring attacks of discomfort or of pain in the ear as a result of eczema, of otitis externa, or of actual pressure of the growth itself. The patient may desire operation to obtain permanent relief. (_c_) If there be deafness of the opposite side from other causes, and the presence of the exostoses is causing deafness of the functionally good ear. (ii) _When both ears are affected._ In addition to the indications already given, operation is advisable on the worse side if there be almost complete obstruction on both sides, accompanied by recurrent attacks of deafness, owing to the narrowed passage of the auditory canal becoming repeatedly blocked from accumulation of cerumen or epithelial débris. _Operation is contra-indicated_ if previous examination indicates that the deafness is due to a chronic middle-ear catarrh or internal-ear disease, as in these cases restoration of hearing, which is the primary object of the operation, will be impossible. =If middle-ear suppuration be present= operation is generally advisable. (i) _In acute middle-ear suppuration_ operation is urgent if there are signs of retention of pus, _provided_ it is impossible to dilate the lumen of the auditory canal. Before resorting to operation an attempt should always first be made to obtain free drainage, as the obstruction may be due merely to inflammatory swelling of the tissues lining the auditory canal. With cessation of the acute inflammation, this swelling may subside and the lumen of the auditory canal again become patent; and if recovery with healing of the tympanic membrane takes place the hearing may again become normal, rendering the operation no longer necessary. (ii) _In chronic middle-ear suppuration_ operation is always indicated if there are symptoms of retention of pus. It is also advisable as a prophylactic measure, although not urgent, even although no acute symptoms are present. =Operation.= =When there is no middle-ear suppuration.=