136 DISEASES OF THE BESPIBATORY ORGANS. 



Pathological Anatomy. On making an opening into the 

 chest with trocar and canula the air escapes with a hissing sound; if 

 the collection of air is great, the lungs are pushed out of position, 

 interfering greatly with respiration. If this condition exists for 

 any length of time, a purulent, and, in rare cases, a sero-purulent, 

 pleuritis is developed, caused by the presence of some irritant 

 agents that have gained admittance into the cavity with the 

 air. 



Clinical Symptoms and Course. There is great difficulty 

 in respiration, and the affected side of the chest-wall is visibly dis- 

 tended, and during respiration it remains almost stationary. "When 

 the heart is pufehed out of position there is a peculiar tympanitic- 

 sound, the pulsations have a metallic echo, and the respiratory 

 bruit is absent. In some rare cases we hear a metallic bruit, which 

 is caus'd by the entrance of air directly into the pleural cavity 

 with each in'^piration. 



Animals in this condition general'y die rapidly, although we- 

 may find rare cases where recovery takes place by an absorption 

 of the air or by the accumulation of a fluid, which in turn becomes 

 rapidly absorbed itself. The treatment consists in tapping th& 

 chest-wall. 



Heernatothorax. 



In consequence of the destruction of some large vessel or vessels, 

 in the lungs or the pleural cavity, from the presence of growths, 

 Ave have extensive hemorrhage into the thoracic cavity. The 

 physical symptoms are similar to those of other pleural exudates;, 

 but this condition comes on very rapidly, and also in this condition 

 the mucous membranes become very pale. When the sympto;iis 

 are not pronounced the operation of puncture will determine the 

 condition positively. Normal hemorrhages are easily and quicklv 

 absorbed, but often there is more or less pleuritis connected with 

 them. Where there is great dyspnoea puncture is always advis- 

 able. 



