348 



CHAPTER XVIII. 



Diseases of the Organs of Breathing. 



sketch of the anatomy of thb organs of breathing general 



remarks on pneumonia, pleurisy and bronchitis ^pneumonia 



pleurisy bronchitis contagious plburo-pneumonia — 



general treatment op pneumonia, pleurisy and bronchitis 



board-ship septic pneumonia congestion of thb lung? sorb 



throat acute nasal catarrh cough bleeding from thb 



nose ^nasal gleet ^broken wind asthma roaring thick 



wind ^highblowing. 



Sketch of the Anatomy of the Organs of 

 Breathing (Fig. 141 J. 



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

 also 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 mndpipe, 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 incomplete cartilaginous rings. It tenninates 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 

 sub-divide into a great number of branches called the bronchia, or bronchial 

 tubes, which finally open into the air-cells of the lungs. The entire rami- 

 fication when isolated has the appearance of a tree, the trachea being the 

 main trunk ; the bronchi and bronchial tubes, the branches ; and the air- 

 cells, the leaves. 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 condition of this mucous membrane, succeeded by an increased 

 secretion of mucus. 



The mucous membrane is what we may call thg^ internal skin which lines 

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

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



