PURUI.ENT PLEURISY (EMPYEMA) IN SOLIPEDS. 



Definition. Inflammation of the pleura, caused or complicated 

 by the pus forming microbes. 



Causes. This may occur as a primary affection, the intro- 

 duction of the pyogenic microorganisms being the essential 

 microbian cause of the disease, or it may supervene on sero- 

 fibrinous pleurisy, the pus germs finding their way later into the 

 inflamed serosa. The possible channels of entry for these mi- 

 crobes are : 



ist. By the blood as in strangles, glanders, contagious pneu- 

 monia, and influenza. 



2d. By the lymph channels, as in fistulous withers, abscess of 

 the intercostal or phrenic region, abscess in the abdomen, and 

 even in strangles, glanders, contagious pneumonia, or influenza. 



3d. By rupture into the pletcral sac of abscesses in the lymph 

 glands, bronchial, oesophagean, mediastinal, subdorsal or pre- 

 pectoral. 



4th. Extension from pulmojiary abscess. Abscess in the lung 

 in cases of pneumonia is quite liable to burst into the pleura, 

 and the suppurative process in inhalation pneumonia will often 

 extend to the serosa. Foreign bodies in the lung from whatever 

 source may lead to purulent extension to the pleura. 



5th. The penetration of a sharp pointed body from the oesopha- 

 gus, or rupture of the oesophagus, in ill-directed efforts for the 

 relief of choking will almost inevitably induce suppuration and 

 empyema. 



6th. External wounds that penetrate the chest, by shot, fork, 

 nail, knife, spur, horn, tusk, pole, shaft, broken spike of wood 

 or metal, of picket, railing or other object, open direct channels 

 for the entrance of pus microbes, and empyema follows. 



Bruises of the chest walls determining abscess may lead to es- 

 cape of pus both externally and internally, and will not only infect 

 but keep a channel open for further entrance of microbes. Sim- 

 ilarly, injuries and necrosis of bones, (ribs, sternum,) maybe- 

 come occasions of empyema. 



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