When the reflector has thus been properly adjusted the patient is required to incline his head backward and open his mouth as wide as possible, when it will be found that the centre of the circle of light falls upon the root of the uvula. A careful examination of the oral cavity, the anterior and posterior pillars, the tonsils, and the wall of the pharynx should be made before the laryngeal mirror is introduced, not only because the condition of these parts often imparts valuable information, but also in order to be sure that no infectious sores be present which might contaminate the instruments to be introduced. The laryngologist cannot be too careful to prevent the carrying of infectious material from one patient to another; and if he should by this preliminary examination discover a specific sore, he should use only such instruments as are reserved for this class of cases, and which are kept in a separate box or drawer of the instrument-case. Everything being in readiness, the laryngeal mirror is held over the lamp, with the glass side down, for a few seconds until it is warm, so as to prevent the condensation of moisture on its reflecting surface, and is then introduced in the following manner: The handle is held between the thumb and fore finger of the right hand like a pen-holder (Fig. 4); the hand is bent {27} backward upon the wrist and held below the chin of the patient. Meanwhile, the protruded tongue is grasped between the folds of a napkin or towel held in the left hand, and gently but firmly pulled out of the mouth. Great care should be exercised to prevent the frænum of the tongue from coming in contact with the sharp edge of the front teeth, for this soon becomes very painful and may prevent a successful examination. Many laryngologists are in the habit of letting the patient hold his tongue, which becomes necessary when operations or applications are to be made to the larynx; but for the purpose of examining only it is better for the observer to hold the tongue, as he thus gains more control over the movements of the head of the patient. [Illustration: FIG. 4. Position of Hand in holding the Laryngeal Mirror.] The mirror is now rapidly introduced into the mouth of the patient, without touching the tongue or the palate, and carried backward until its rim touches the wall of the pharynx, when it is lifted upward, carrying on its back the uvula, and the stem is brought into the angle of the mouth, so as to be out of the line of vision (Fig. 5). In this position the light of the reflector will fall upon the reflecting surface of the laryngeal mirror, and will be reflected downward so as to illuminate the laryngeal cavity and reflect the laryngeal image into the eye of the observer. [Illustration: FIG. 5. Diagram of Section of Head, showing the Position of Laryngeal Mirror in the Pharynx.]