The Voice. 373 



subject, but no other word conveys an idea of its shrill- 

 ness. 



If a horse cries from pain (which is very rare) as during 

 a surgical operation, the cry is a muffled one and short ; it 

 is a groan rather than a cry. 



The larynx is divided into a respiratory portion and 

 a vocal portion; the latter comprises the region of the 

 vocal cords and their attachment, the former the glottal 

 opening formed by the arytenoid cartilages. 



Production of Sound. — If air be forced between the vocal 

 cords so as to cause them to vibrate, sound is produced. 

 The various modifications of that sound are produced in 

 the air-passage anterior to the larynx, such as the posterior 

 nares, the nostrils, and in the horse the false nostril and 

 perhaps the guttural pouch. How far the latter assists in 

 producing the voice is not clear ; but it has been considered 

 that it plays some part in the process, though Colin men- 

 tions that, when he opened the guttural pouches, the horse's 

 neigh had lost but little, if any, of its ordinary character. 

 I have previously expressed myself that this remarkable 

 pouch is perhaps more intimately connected with the sense 

 of hearing. In the false nostril sounds are certainly pro- 

 duced of an expiratory character, such as the peculiar snort 

 of a frightened or ' fresh ' horse. The sacs during these 

 sounds are considerably dilated. 



During ordinary respiration, the vocal cords are apart, 

 but when voice is produced, the edges of the cords are 

 approximated and made parallel, so that the rush of air 

 passing between them causes them to vibrate, the tone 

 produced depending on the tension of the cords. If air be 

 forced through a dead larynx, and the tension of the cords 

 increased and decreased, a sound remarkably like a neigh 

 may be produced. 



The ventricles of the larynx, cavities of the mouth, nose, 

 and pharynx, act as resonators, being tilled with air. The 

 ventricles of the larynx also allow of the free vibration of 

 the vocal cords ; they are very large in the horse and 

 howling monkeys. 



