THE VOICE AND SPEECH. 441 



evidently iii those of coughing and other forcible respiratory move- 

 ments. 



The laryngoscope is an instrument employed in investigating dur- 

 ing life the condition of the pharynx, larynx, and trachea. It consists 

 of a large concave mirror with perforated centre, and of a smaller mir- 

 ror fixed in a long handle. It is thus used: the patient is placed in a 

 chair, a good light (argand burner, or lamp) is arranged on one side of, 

 and a little above his head. The operator fixes the large mirror round 

 his head in such a manner, that he looks through the central aperture 

 with one eye. He then seats himself opposite the patient, and so alters 

 the position of the mirror, which is for this purpose provided with a ball 

 and socket joint, that a beam of light is reflected on the lips of the pa- 

 tient. 



The patient is now directed to throw his head slightly backwards, 

 and to open his mouth; the reflection from the mirror lights up the 

 cavity of the mouth, and by a little alteration of the distance between 

 the operator and the patient the point at which the greatest amount of 

 light is reflected by the mirror in other words its focal length is 

 readily discovered. The small mirror fixed in the handle is then 

 warmed, either by holding it over the lamp, or by putting it into a ves- 

 sel of warm water; this is necessary to prevent the condensation of 

 breath upon its surface. The degree of heat is regulated by applying' 

 the back of the mirror to the hand or cheek, when it should feel warm 

 without being painful. 



After these preliminaries the patient is directed to put out his tongue, 

 which is held by the left hand gently but firmly against the lower teeth, 

 by means of a handkerchief. The warm mirror is passed to the back of 

 the mouth, until it rests upon and slightly raises the base of the uvula, 

 and at the same time the light is directed upon it: an inverted image of 

 the larynx and trachea will be seen in the mirror. If the dorsum of the 

 tongue be alone seen, the handle of the mirror must be slightly lowered 

 until the larynx comes into view; care should be taken, however, not to 

 move the mirror upon the uvula, as it excites retching. The observa- 

 tion should not be prolonged, but should rather be repeated at short in- 

 tervals. 



The structures seen will vary somewhat according to the condition of 

 the parts as to inspiration, expiration, phonation, etc.; they are (Figs. 

 307) first, and apparently at the posterior part, the base of the tongue, 

 immediately below which is the arcuate outline of the epiglottis, with 

 its cushion or tubercle. Thea are seen in the central line the true vocal 

 cords, white and shining in their normal condition. The cords approxi- 

 mate (in the inverted image) posteriorly; between them is left a chink, 

 narrow whilst a high note is being sung, wide during a deep inspiration. 

 On each side of the true vocal cords, and on a higher level, are the pink 

 false vocal cords. Still more externally than the false vocal cords is the 

 aryteno-epiglottidean fold, in which are situated upon each side three 

 small elevations; of these the most, external is the cartilage of Wrisberg, 

 the intermediate is the cartilage of Santorini. whilst the summit of the 

 arytenoid cartilage is in front, and somewhat below the preceding, being 

 only seen during deep inspiration. The rings of the trachea, and even 

 the bifurcation of the trachea itself, if the patient be directed to draw a- 

 deep breath, may be seen in the interval between the true vocal cords. 



