CLINICAL EXAMINATION 285 While the normal appearance is readily recognized after a little practice, the beginner experiences considerable difficulty in distinguishing many abnormal conditions. Where difficulty exists, the short process and handle of the malleus should be looked for in the first instance, because if they are seen there is no doubt that the structure they lie in is the drumhead, however much Fig. 158. Siegle's speculum. its appearance may be altered. When they are not detected the observer must attempt to estimate the depth of the structure at which he is looking. If it is obviously nearer the eye than the membrane, the appearance may be due to a polypus, granulation tissue, wax, a foreign body or some projection from the meatal wall. If the appearances are not comparable with any condition with which the observer is familiar, the ear should be syringed or mopped out, as the presence of even a little pus or a flake of wax or desquamated epithelium may be quite misleading and give rise to an incorrect diagnosis. A minute perforation of the membrane appears as a black spot because, as it is small, the middle ear is not lit up through it. A healed influenza! bulla gives a somewhat similar appearance. A larger perforation allows light to illuminate the middle ear cavity. Perforations have clear-cut edges unless they are due to trauma in which case the edges may be ragged. A cicatrix is usually transparent and may appear like a dry perforation (Plate X, 18), but unless it is adherent to the medial wall of the middle ear it may be distinguished from a perforation by means of a Siegle's pneumatic speculum (Fig. 158). This is a speculum which expands into a small chamber and is closed at its outer end by a lens. A small hollow tube, to which a valveless rubber ball is attached by rubber tubing, is let into the side. The speculum is introduced into the meatus, which it should fit closely, and an enlarged view of the drumhead is obtained. By alternately compressing and releasing the bulb, the air in the meatus is alternately condensed and rarefied. In the case of a cicatrix each movement of the rubber ball makes it flap in and out (Plate X, 19) while a perforation shows no movement, although, if the middle ear contains secretion, some discharge may be sucked out through the perforation.