LXVII.] LARYNGOSCOPE. 315 



LESSON LXYIL 



LARYNGOSCOPE— VOWELS. 



1. The Laryngoscope is used to investigate the condition of the 

 pharynx, larynx, and trachea. Various forms are in use, but they 

 all consist of — (i) One or more small, usually circular, plane mirrors 

 fixed to a metallic rod at an angle of 120° ; the metallic rod fits 

 into a suitable handle, and is fixed by means of a screw. (2) A 

 large concave mirror of about 20 cm. focus, perforated with a hole 

 in the centre, and secured to the operator's forehead by means of a 

 circular band passing round the head. The mirror itself is fixed 

 in a ball-and-socket joint, so that it can be moved freely in every 

 direction. 



A. Practise first of all on a model of the head and larynx 

 provided for the purpose. 



B. On a Living Person. — (a.) Place the patient upright in a 

 chair. A good source of artificial light — e.(/., a suitable Argand 

 lamp — is placed near the side of the patient's head, a little above 

 the level of his mouth. The incandescent lamp gives a brilliant, 

 clear, and steady light. INIackenzie's rack-movement lamp is a most 

 convenient form. The observer seats himself opposite and close to 

 the patient; places the large mirror on liis forehead, and either 

 looks through the central hole in it with one eye, or raises it so 

 that he can just see under its lower edge. 



(b.) Seated in front of the patient, the observer directs a beam 

 of light until the lips of the patient are brightly illuminated. The 

 patient is then directed to incUne his head slightly backwards, to 

 open his mouth wide, and protrude his tongue. Place a clean 

 handkerchief over the tongue, and give the patient the hand- 

 kerchief to hold, which secures that the tongue is kept protruded 

 and well forward. Move the large mirror until the uvula and 

 back of the throat are brightly illuminated, the operator moving 

 his head slightly to and from the patient until the greatest 

 brightness is obtained. 



(c.) Take the small laryngeal mirror in the right hand, and warm 

 it gently over the lamp to prevent the condensation of moisture on 

 its surface. Test its temperature on the skin of the cheek or the 

 back of the hand. Holding the handle of the mirror as one does a 

 pen, rapidly carry it horizontally backwards, avoiding contact with 

 any structures in the mouth, until its back rests against the base of 

 the uvula. At the same time, direct the beam of light upon the 



