220 On the Laryngoscope. | April, 
Gibb, and Mandl should not be omitted whilst referrmg to 
labourers in this field. 
2. The Instrwment.—The most essential part of the Laryn- 
goscope is the laryngeal mirror. It should be made of silvered 
plate-glass, and set at an angle of 120° with its stem. It may be 
circular, or square with the angles rounded, and if from vs>—xo of 
an inch in diameter, will be found most generally useful. The 
illuminating silvered glass mirror ranks next in importance; it 
should be slightly concave, perforated in the centre, of about 384 inches 
in diameter, and possessing a focal power of 14 inches. It is des'r- 
able to have the mirror attached to the frontal pad or spectacle- 
frame, by means of a ball and socket-joint, and so arranged as to be 
worn at pleasure, either in front of the eye or on the forehead. As 
to the light, nothing equals the solar rays; but as they are not 
always to be obtained, it is necessary to resort to artificial illumin- 
ating sources. The bright, steady flame of a good German lamp 
—especially if a Tobold’s condenser is adapted to it — leaves little to 
be desired. A tongue-depressor is often requisite: one composed of 
vulcanite, with its under-surface serrated, so that some traction may 
be exerted on the tongue, is found by the writer preferable to any 
other form. 
8. Mode of employing the Laryngoscope.—The individual to 
be examined should be seated upright in a chair, with the head 
slightly inclined backwards, the mouth widely opened, and the 
tongue protruded. If the solar rays are available, his back should 
be turned towards the sun, but if artificial light is necessary, the 
lamp should be placed on a table by his side, and at such an eleva- 
tion as to be on a level with the ear. The observer, being seated 
immediately in front of the observed, and having his illuminating 
mirror on his forehead, or in front of either eye (im which latter 
case he gazes in the direct axis of the illuminating rays), should 
hold the protruded tongue firmly between the fore-finger and thumb 
of the left hand, previously enveloped in a cloth or handkerchief. 
The rays proceeding from the illuminating source are easily directed 
by a little adjustment of the mirror into the throat, having not only 
undergone reflexion, but concentration. The laryngeal mirror, 
being held like a pen in the right hand, is to be heated over the 
lamp, to prevent the condensation on it of moisture. Before its 
introduction, the temperature of the mirror should always be tested 
by placing it on the back of the hand or on the cheek, to prevent 
the possibility of burning the throat. Having been carefully passed 
over the base of the tongue, so as to avoid contact with that organ, 
it should be made to rest on and slightly raise the uvula—that 1s, if 
we wish to look vertically down the laryngeal tube. The base of 
that unruly member, the tongue, has very often a great tendency to 
rise towards the palate, thus obstructing both light and vision. 
