DISEASES OF THE RESPIRATORY ORGANS. 



We now come to a most important class of diseases, affect- 

 ing the breathing apparatus, with which every stock raiser, 

 farmer, stable keeper, and horsemen in general should be 

 well acquainted. 



The organs chiefly subject to attack are the nasal cavities, 

 the larynx, the bronchial tubes, the lungs, and the pleura 

 investing the lungs. Each and every one of these parts are at 

 times the subject either of acute or chronic inflammation. The 

 greater number of the organs of digestion, as well as the 

 organs of respiration, are lined by a delicate tissue called 

 mucous membrane. It is this membrane that is affected in 

 nearly all of the diseases above mentioned. This is a fact 

 worth remembering : for instance, inflammation of the mu- 

 cous membrane of the nostrils is called "catarrh;" of the 

 bronchial tubes, "bronchitis," and so on. A few words on 

 inflammatory action produced on this membrane in par- 

 ticular will not be here out of place. Wherever this tissue 

 is found the same effects are produced on it by stimulation, 

 irritation, congestion, or inflammation. 



A certain portion of mucus constantly moistens these 

 surfaces in a state of health, but during disease it is altered 

 both in character and amount. The general statement is, 

 that when a mucous membrane is inflamed its secretion of 

 mucus is at first arrested, then increased, and finally per- 

 verted in character. 



A right understanding of these facts will simplify in a 

 great measure a proper answer to the question so often asked 

 in these cases, "What is the matter with the horse.? " or a 



