236 THE HOESB IN HEALTH AND DISEASE 



"pleuritic ridge," extending from the lower ends of the false ribs to 

 the external angle of the ilium, is seen with each respiratory move- 

 ment. 



Generally speaking, the course of pleurisy is slow. Recovery is 

 not always complete, for adhesions occur between the pleura cover- 

 ing the lungs and that lining the walls of the thorax. This results 

 in permanent interference with the normal expansion and con- 

 traction of these organs. 



Treatment is similar to that mentioned for pneumonia. If pain 

 is so great as to cause distress in breathing, I ounce of chloral 

 hydrate may be given. 



HEAVES 



Heaves is a chronic, non-infectious condition of difficult 

 breathing in which the act of expiration is longer than the inspira- 

 tory act. Heaves is not accompanied by fever and is not directly 

 fatal. The chief pathologic change is confined to the lungs, the 

 thin, dehcate air-sacs of which break down and lose their normal 

 contractile power. 



Bulky foods, indigestible foods, and foods which ferment easily 

 all lead to overdistention of the stomach and to excessive pressure 

 upon the diaphragm. Dusty fodder, especially hay which has been 

 wet during harvest, or over-ripe hay, is harmful and may induce 

 heaves. 



Symptoms. — A peculiar, dry, droning cough is heard before the 

 difficult breathing, later so characteristic, is noticeable. The 

 cough is explosive in nature and soon becomes very marked; 

 furthermore, it is aggravated by dust and is accompanied by 

 flatulence. Inhalation is normal, but exhalation is labored and 

 difficult. This requires the patient to make a special effort to 

 force out the air. As a result, there occurs a "double-pumping 

 action" of the flanks with two expulsive efforts instead of one. 

 This produces the so-called "heave-line" seen along the flanks of 

 affected horses. With exercise these symptoms are much intensi- 

 fied. Disguised cases can be detected, or tests can be carried out 

 by feeding all the dusty hay the horse will eat, then giving plenty of 

 water and driving him briskly. 



Treatment. — After the disease is once developed it is impossible 

 to effect a cure for anatomic structures have been destroyed, so 

 treatment can only be palliative. It is said that horses suffering 



