If the inflammatory process, instead of being localized as a furuncle, extends to the subcutaneous tissues, and especially if it is accompanied by much pain, pyrexia, and occlusion of the external meatus, _linear scarification_ may become necessary. After incision, the contents of the furuncle are rapidly scooped out with the curette (Fig. 178, A). Slight hæmorrhage may occur, but can be arrested at once by plugging the meatus for a minute with a strip of sterilized gauze. The auditory canal is finally syringed out with a warm aqueous 1 in 5,000 solution of biniodide of mercury and firmly plugged with gauze soaked in a 10% solution of carbolic acid in glycerine; a hot fomentation being afterwards applied to the side of the head. [Illustration: FIG. 178. BURKHARDT-MERIAN’S AURAL INSTRUMENT. A. Curette. B. Myringotome. C. Furunculotome. D. Hook for removal of foreign body. ] If the operation has been performed under a local anæsthetic (and this should only be done if a solitary furuncle is present), the pain is usually too great to permit of firm packing of the auditory canal. This after-packing, however, should be carried out, if possible, for the following reasons: firstly, it presses out the contents of the furuncle; secondly, it prevents auto-infection from one hair follicle to another; and thirdly, it tends to dilate the auditory canal. =After-treatment.= If the furuncles have occurred during the course of a middle-ear suppuration, the gauze plugging must be removed within a few hours after the operation. The ear is then syringed out once or twice daily with a warm solution of lysol or carbolic acid, a small wick of gauze soaked in a 10% solution of carbolic acid in glycerine being afterwards inserted along the meatus. If there be no accompanying middle-ear suppuration, the packing should not be removed for at least twenty-four hours. The pain produced by the first dressing may be severe, but can be usually avoided by first soaking the gauze with 5% solution of cocaine for a few minutes before removal and then gently withdrawing it whilst the ear is being syringed with a warm aseptic lotion. For the next two or three days it is sufficient to insert a drain of gauze soaked in a 1 in 3,000 alcoholic solution of perchloride of mercury. =Results.= Although cure may be expected, it is not uncommon for further furuncles to occur in crops at repeated intervals. This is due to auto-infection of the hair follicles, which to a large extent may be prevented by painting the surface of the auditory canal daily, for at least two or three weeks, with an oil containing a drachm of nitrate of mercury to the ounce. In the case of diffuse inflammation, although relapses are uncommon, superficial necrosis of a portion of the bony meatus may afterwards occur as a result of involvement of its periosteal lining. If this takes place, stenosis of the auditory canal may afterwards occur from subsequent cicatrization.