LARYNX AND P HO NATION. 357 



the higher notes, the larynx rises, the laryngeal muscles being 

 contracted for this purpose and the head thrown back ; while, 

 for the lower notes, the larynx descends and the chin is de- 

 pressed. These are well-known movements, and a patient 

 examined with the laryngoscope is sometimes made to utter 

 high notes, because exploration of the larynx is more readily 

 performed when it is elevated. Attempts have been made 

 to explain these phenomena by comparing them with those 

 produced in wind-instruments. In the first instance, the part 

 under the glottis was supposed to be elongated, and the part 

 above the glottis contracted, and vice-versa, in the second or 

 emission of high notes. This explanation, however, is ren- 

 dered useless by the fact that the same phenomena are ob- 

 served when we produce the sound in inspiration ; thus, 

 although the physical performance of the organs is reversed, 

 the larynx always rises in the upper notes and falls in the 

 lower. 



The elevation of the larynx may be much more satisfac- 

 torily explained by considering that the walls of the trachea 

 act as a resonant organ, and that, consequently, in order to 

 heighten a certain sound, they must be in a state of peculiar 

 tension, for the same elastic wall does not vibrate indiffer- 

 ently with all sounds : its tension must be modified in differ- 

 ent cases. The higher the note, the more tense the resonant 

 parts are. 



The entire nasal system, consisting of the nasal chambers 

 and the frontal, ethmoidal, and maxillary sinuses, is connected 

 with these organs of sound. These cavities are not intended 

 for secretions ; but, on account of their coa,ts being formed 

 of somewhat delicate elastic lamellaB, they "readily vibrate. 

 Any injury to these organs considerably modifies the tone of 

 the voice. The cartilages of the nose are also resonant 

 organs, as everybody knows that when they are hindered 

 from vibrating the tone of the voice is altered in a peculiar 

 manner. 



The vibration of the trachea, the bronchi, the lungs, and 

 the cage of the thorax, also serves to intensify the sounds 

 produced by the larynx. The voice undergoes a change in 

 diseases of the trachea, the bronchi, and the lungs. 



The articulation of speech, which differs greatly from the 

 simple cry, or sound made by the larynx, are almost entirely 

 produced by the working of these sonant parts, and chiefly 

 by modifications in the apertures of the lips and the back 

 part of the throat.. 



