324 THE SENSES 



which in turn hand them over through the fenestra ovalis to the 

 fluids of the internal ear, through which media they reach the 

 auditory filaments, are conducted to the brain and given proper 

 recognition. 



The Production of the Voice. 



The production of the voice is not connected with the special 

 senses, but its consideration will be introduced here for the sake 

 of convenience. 



The Larynx is the organ of voice. It is a cavity closed ex- 

 cept for its openings above and below. It conisists of four car- 

 tilages cricoid, thyroid and two arytenoid joined together by 

 ligaments and muscles. The vocal cords are attached poste- 

 riorly to the bases of the movable arytenoid cartilages and ante- 

 riorly to the angle between the alae of the thyroid. The muscles 

 serve to move the cartilages and thus to separate or approximate 

 and to render lax or tense the vocal cords. 



Production of Sound. The human voice is produced by 

 vibrations of the vocal cords, which vibrations are set up by 

 currents of expired air. 



Movements of the Vocal Cords. These are those taking 

 place (i) in respiration and (2) during vocalization. 

 j, i. In Respiration. When the cords are "passive" they are 

 approximated anteriorly and separated posteriorly, so that 

 the interval between them (rima glottidis) is triangular. This 

 interval becomes a little wider during inspiration and a little 

 narrower during expiration. 



2. In Vocalization. The production of sound in the larynx 

 involves an approximation of the cords and an increase in their 

 tension. They are made more nearly parallel by the approach 

 of the arytenoids to each other, and the rima glottidis assumes 

 the shape of a mere chink. The tenser the cords, the higher the 

 note produced; usually also the closer the cords are brought to- 



