350 



CHAPTER XVIII. 



Diseases of the Organs of Breathing. 



sketch of the anatomy of the organs of breathing general 



remarks on pneumonia, pleurisy, and bronchitis pneumonia 



— - pleurisy ■ bronchitis contagious pleuro-pneumonia 



general treatment of pneumonia, pleurisy, and bronchitis — • 



board-ship septic pneumonia congestion of the lungs sore 



throat acute nasal catarrh cough bleeding from the 



nose nasal gleet broken wind asthivia roaring ^thick 



wind highblowing. 



Sketch of the Anatomy of the Organs of 

 Breathing {Fig. 141). 



The passages from the Eostrils open into a cavity called the pharynx, which 

 al?o communicates with the mouth through an opening termed the isthmus, 

 over which the soft palate is suspended, like a valvular curtain, in order to 

 keep it shut, except during the passage of food and water ; hence, the horse 

 is unable to breathe freely through his mouth. The ivi'nd]}^]^^, or trachea, 

 opens into the pharynx by means of a short cartilaginous tube, the larynx, 

 which is the organ of voice, and is situated between the angles of the branches 

 of the lower jaw. When it is inflamed, we have laryngitis, or sore throat. 

 The larynx is guarded from the entrance of food, water, &c., by a cartilaginous 

 valve called the epiglottis, over which the mouthful of food, or " go-down " of 

 water, passes. The windpipe, or trachea, is an elastic tube formed of incom- 

 plete cartilaginous rings. It terminates at the base of the heart., and splits 

 up into two tubes — the right and left bronchi — which respectively go to the 

 right and left lung. These bronchi further subdivide into a great number of 

 branches called the bronchia, or bronchial tube><, which finally open into the 

 air-cells of the lungs. " The entire ramification when if-olated has the appear- 

 ance of a tree, the trachea being the main trunk ; the bronchi and bronchial 

 tubes, the branches ; and the air-cells, the leaves " (" Strangeways' 

 Anatomy "). The nasal passages, the pharynx, larynx, and bronchial tubes, 

 are lined with mucous membrane. Thus, in sore throat and bronchitis 

 (inflammation of the bronchial tubes), we have, at first, a dry and inflamed con- 

 dition of this mucous membrane, succeeded by an increased secretion of mucus. 



The mucous membrane is what we may call the internal ^^kin which lines 

 various hollow organs, such as the nostrils, windpipe, mouth, gullet, stomach, 

 intestines, eyelids, interior of the ears, bladder, and urethra. It secretes a 

 slimy fluid [mucus), which is known as "phlegm," when it is discharged from 

 the windpipe. 



The lungs are composed of a spongy substance, which is made up of a vast 



