The second method is to mount the electric lamp on the head mirror in such a way that it projects a little from the surface and is a little to one side of the centre of the reflector (Fig. 3). The light is then thrown forward in a cone, and can be directed with great ease into the mouth of the patient. Since thus the source of the light moves with the mirror, the observer can follow the motions of the patient more easily; and if, in the first place, an easy position of the head has been assumed when adjusting the light, much less {25} fatigue is experienced by the examiner with this apparatus than when the light is reflected from a stationary source. Still another mode of using the incandescent lamp, which was suggested by Trouvé, is to mount the lamp within a tube one end of which is closed by a plano-convex lense, while the other end is covered by a metal cap carrying in its centre a ball-and-socket joint, by means of which it is fastened to the frontal plate of the head band. In this way the light with its condensing apparatus is carried on the forehead like the head mirror. Sunlight is certainly the best source of light for the illumination of the interior of the larynx and nasal cavities, but, unfortunately, it is not available at all times and in all localities. When it can be obtained, however, the student should not neglect the opportunity, and should not be deterred from using it for examination by the little extra apparatus and trouble necessary. The most convenient plan is to place a small plane mirror mounted upon a stand in such a manner that it can be turned in any direction, such as a small toilet-glass, in the direct rays of the sun coming through a southern window. Then turn the mirror until the reflection falls upon a second plane mirror supported by a jointed arm and placed in a distant corner of the room, and in front of the chair upon which the patient is seated, with his back to the first mirror. The light from the second mirror is then thrown into the patient's mouth in the same manner as when a light concentrator is used. The second mirror may also be mounted on the head band and used as a head reflector, but this latter plan is not as satisfactory, because the reflected light from the first mirror is apt to strike the observer's eye and temporarily blind him.