OTHER NON-COMMUNICABLE DISEASES 349 



cavity, or so roughen the smooth contact surfaces of the pleura 

 that friction is produced with each respiration. 



Causes. — There is a prevailing idea that pleurisy is usually 

 caused by exposure to cold draughts, especially after the animal 

 has been very hot and sweaty. It appears, however, more fre- 

 quently after a disease such as pneumonia, glanders, or tuber- 

 culosis has paved the way. Puncture wounds of the thorax 

 always cause pleurisy. 



Symptoms. — If the case is seen early, pain and chills are the 

 noticeable symptoms. The temperature . ranges from 105° to 

 106°F. and the pulse is quickened. Breathing is altered, in that 

 an effort is made to restrict movement of the chest wall. This 

 results in additional work for the abdominal muscles, and the 

 typical "pleuritic ridge," extending from the lower ends of the 

 false ribs to the point of the hip becomes a marked symptom. 

 Horses persistently stand, while cattle lie down when affected 

 with pleurisy or pneumonia. 



Generally speaking, the course of pleurisy is slow. Recovery 

 is not always complete for adhesions occur between the pleura 

 covering the lungs and that lining the walls of the thorax. This 

 results in permanent interference with the normal expansion and 

 contraction of these organs and leaves the horse "defective in 

 the wind." 



Treatment. — This is similar to that mentioned for pneumonia. 

 If pain is so great as to cause distress in breathing, J^ ounce of 

 chloral hydrate may be given. If much fluid has accumulated 

 in the thorax, it should be drawn off by means of a trocar and 

 canula. 



PNEUMONIA 



Any inflammatory condition of the lungs is spoken of as 

 pneumonia. In this, as in all forms of inflammation, more blood 

 is brought to the inflamed tissues than normally. This results in 

 a part of the fluid portion of the blood passing into the minute 

 air-sacs of the lungs. The presence of this exudate reduces the 

 capacity of the lungs to deliver oxygen to the blood and remove 

 carbon dioxid from it. Later the fluid thickens by the addition 

 of mucus and fibrin, forming a thick phlegm. This causes the 

 involved portion of the lung to become a solid mass that resembles 

 liver, so it is said to be hepatized. 



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