156 PEACTICE OF EQUINE MEDICINE. 



mur, or, if bronchial dilatation is present, there is cavernous or 

 amphoric respiration. 



The affected side is sunken, and not so movable. 



Cough is present, and there is some interference with the 

 breathing on exertion. 



Indicate the treatment. 



Look after the general health of the animal; give tonics and 

 absorbents, the iodide of potassium being the best. 



Good food, moderate exercise or work, and fresh air. 



PULMONAKY EMPHYSEMA. 



Name the synonyms. 



Emphysema, heaves, broken wind, chronic dyspnoea. 



Define pulmonary emphysema. 



This is a chronic, non-febrile, pulmonary disease, with either 

 a dilatation or rupture of the vesicular structure of the lungs, and 

 characterized by a dry abortive cough and a double expiratory act. 



Give the forms. 



There are two principal forms — the vesicular and the interlob- 

 ular. 



What is the difference? 



The vesicular form is a simple dilatation of the alveoli and 

 lobules, with atrophy of the interalveolar walls, while the intervesic- 

 ular or interstitial form is a rupture of the walls of the air-cells, 

 and the air escapes into the connective tissue which binds the air- 

 cells together. There is an increased intralobular pressure, causing 

 air to gain entrance into the interlobular connective tissue and into 

 the lymphatic spaces. 



What is the aetiology ? 



In the human subject, violent efforts at coughing, where the 

 bronchial tubes are filled with mucus. 



Men who play wind instruments or do heavy lifting suffer 

 with emphysema. 



In the horse, rapid work, heavy draft work, may be a cause. 



There is also a hereditary predisposition, there being a weak- 

 ness in the walls of the air-cells. 



