DISEASES OF THE RESPIRATORY ORGANS. 93 



has undergone some decomposition. More frequently it is the 

 result of a wound penetrating the walls of the chest with its 

 edges pressed inward so that they admit the air from without 

 while the chest is dilating, but close like a valve when it is 

 contracting. A little thus entering with each breath and none 

 escaping, the lung is soon compressed into a small solid mass 

 against the lower end of the windpipe. The same may happen 

 from a broken rib having torn the surface of the lung, even 

 without any external wound. A little air escaping from the 

 lung with each respiration the cavity soon becomes filled and 

 the lung compressed and collapsed. 



Treatment is limited to the prevention of the introduction of 

 air through an external wound, should such exist ; the relief of 

 pain by opium and other anodynes ; the management of the 

 resulting pleurisy on ordinary principles ; and the drawing off 

 of the accumulated air by a needle-like tube and aspirator, or 

 even by a small cannula and trocar. Spontaneous recovery 

 often takes place, the wound being closed by inflammatory 

 exudation and the air absorbed. In cases dependent on 

 decomposition of the products, both gas and liquid should be 

 drawn off and a weak solution of carbolic acid (one part to 

 two or three hundred water) thrown in, in small quantity. 



ABSCESS OF THE INTERCOSTAL SPACES. 



This occurs especially in the horse as a result of pleurisy, a 

 diffuse swelling appearing at some part of the walls of the chest, 

 tender and pitting on pressure, and, finally, softening in the 

 centre, bursting and discharging a yellowish or whitish matter. 

 The patient should be well fed, and poultices or warm fomen- 

 tations continuously applied to the part until there is softening 

 in the centre, when it may be freely laid open. Continue to 

 support the patient by nourishing food, stimulants, and tonics. 



