16 THE NATURE AND TREATMENT OF 



the patient does not improve, and the danger appears imminent, 

 tracheotomy should be performed. 



DESCRIPTION OF THE LARYNX. 



The larynx is seated at the upper part of the windpipe, to 

 which it is joined ; it occupies that part known as the throat, be- 

 tween the broadest part of the angles of the jaw. It is com- 

 posed of several cartilages, which are under the control of the 

 laryngial muscles. These cartilages are so contrived as to be 

 movable on each other, in various directions. 



The j^r5^ cartilage is named thyroid, or shieldlike. It forms 

 the most extensive part of the larynx, and protects the other 

 parts from external injury. 



The second cartilage is named cricoid, or ring-like cartilage. 

 It overlaps the first ring of the trachea or windpipe, in the 

 form of a helmet. 



Thirdly, there are two ewer-shaped cartilages, termed ary- 

 tenoid ; they are found on the upper and back part of the 

 trachea. They form a canal which leads to the glottis. 



The fourth cartilage is named epiglottis, in consequence of 

 being situated upon and over the glottis ; it is the door-keeper 

 of the larnyx, and every particle of food, or drop of water, 

 which the animal swallows must pass over it ; if it fail to per- 

 form its function, for a single moment, when the animal is 

 either drinking or eating, death is sure to follow. But the ox 

 is rather more favored, in the mechanism of the epiglottis, than 

 the horse. The epiglottis of the horse is just adapted to the 

 calibre of the glottis, he being a non-ruminant ; but in the case 

 of the ox, the rough, unmasticated particles of food have to be 

 returned to the mouth for a second mastication ; this would peril 

 the life of the animal if he had no other protection than that 

 found in the larynx of horses. The fact is, the epiglottis of 

 cattle ; instead of being confined to the calibre of the rim of the 

 of the glottis, overlaps it ; and this securely protects the parts 

 from the accidents which may occur in the process of remasti- 

 cation. 



