166 DISEASES OF THE KBSPIKATOKY OEGANS. 



pleurisy. 



This is inflammation of the serous coverings of the lungs 

 and chest cavity. It is produced by the same causes which result 

 in inflammation of the lungs, more particularly in sudden 

 changes in temperature, which tend to thoroughly chill the 

 whole system. It is frequently seen following dipping in the 

 late fall or sheep-washing in the spring, or may arise from the 

 extension of inflammation from parts contiguous to the pleural 

 surface or from direct injury, or adventitious growths involving 

 the pleura, such as cancer, etc. 



Symptoms. 



Spasmodic pains will be observed, causing the sheep to grunt, 

 grind its teeth and appear anxious and uneasy. The other symp- 

 toms resemble closely those of inflammation of the lungs, except 

 that the pulse is hard and strong, the ears and legs become cold, 

 the flanks heave, while the ribs appear fixed. This stage of the 

 disease may last two or three days, recovery taking place by a 

 cessation of the inflammation and a return of the parts to their 

 normal condition. Shoidd this not occur, however, it is very 

 liable to terminate fatally, but death may be deferred for a 

 week or even ten days. Prior to this second stage the appetite 

 is lost, but as the effusion from the inflamed pleural surfaces 

 takes place, resulting from the inflammation, the sheep com- 

 mences to feed, the extremities get warm and an apparent change 

 for the better takes place. This, however, is only the fore- 

 runner of the third stage of the disease. The effusion increases 

 till the chest cavity becomes fllled with a watery serous liquid, 

 the respirations once more become labored, the eyes become 

 glassy, and the sheep soon dies, virtually from suffocation. The 

 effusion in the chest cavity is termed in scientific works hydro- 

 thorax, which may at the commencement terminate favorably 

 through a cessation of the effusion and its absorption by the 



