=Non-surgical treatment.=—See chronic suppurative otitis media. We have had a few cases that were seemingly permanently cured by non-surgical treatment, but believe they are rare. =Indications for Operation.=—1. Recurrent exacerbation of acute or chronic otitis media. 2. Constant discharge which resists treatment for chronic suppurative otitis media. 3. Continued pain or recurrent pain and swelling following acute otitis media. 4. Open sinus into mastoid either external or through meatus. 5. Cholesteatoma. 6. Symptoms of labyrinthine or brain involvement following acute otitis media. 7. Definite evidence of bone disintegration in mastoid. As stated above, none of these are definite indications. The whole group of signs and symptoms are to be considered. Chronic Suppurative Otitis Media =Etiology.=—Chronic suppurative otitis media usually results from an unsuccessfully treated acute otitis media. If in acute otitis media there has been bone erosion or extensive destruction of the mucous membrane by a virulent infection, chronic suppuration is likely to result. A persistent mastoid infection following otitis media is likely to result in chronic otitis media and this is strong argument for early mastoid operation. 1. Otitis media resulting from some virulent infection such as the recent influenza pandemic or scarlet fever is always more likely to result in mastoiditis and chronic suppuration of the middle ear. 2. Such infectious agents as streptococcus, staphylococcus, long-chain pneumococcus or bacillus influenzæ are likely to result in chronic suppurations. 3. Lowered vitality from any cause. 4. Inefficient drainage from failure to aspirate the Eustachian tube, delayed perforation or failure to lance drum sufficiently early. 5. Mastoid necrosis, which maintains drainage into the tympanic cavity. 6. Abnormal granulations, polypi, etc. in tympanic cavity. 7. Chronic inflammation with suppuration of the epipharynx or Eustachian tubes. 8. Cholesteatoma resulting from perforated drum and growths of epithelium extending into the middle ear cavity. =Diagnosis.=—The diagnosis is easy because nearly every case of discharging ear without pain is chronic suppurative otitis media. The determination of the exact nature of the condition present is not only very important but very difficult. Differential diagnosis consists in determining the nature of the infecting organism and the nature and extent of the pathology.