170 MANUAL OF EQUINE MEDICINE. 



are liable to exacerbations from extremes of heat and cold, 

 and other atmospheric changes. 



The chest is rounder than it should be, and the thoracic 

 movements are much impaired, while the movements of 

 the abdomen are violently put into action during a paroxysm 

 of cough. 



In well-developed cases the loud sonorous wheezing 

 noise may be distinctly heard while near the animal. If 

 the chest be carefully auscultated, rhonchus and sibilus 

 will be audible all over the chest, but the sounds vary 

 much in character, even in the same animal, at different 

 times. 



The respiratory murmur is diminished or absent. In the 

 inspiration a ' cooing rhonchus or friction sound ' is 

 heard ; whereas a weak crepitus is audible in the pro- 

 longed expiration. Percussion reveals increased resonance 

 in various parts of the chest. In confirmed cases the di- 

 gestive organs are weak and easily deranged, the bowels 

 are tympanitic, and borborygmi are frequent. The horse 

 is debilitated and unthrifty, and the coat is often harsh, 

 dry, and scurfy. When worked, he is easily fatigued, and 

 perspires easily, and the bowels are generally loose. 



Morbid Anatomy. — The pathological lesions found after 

 death, which is in most cases due to some other disease or 

 to accident, are very variable in character. 



The organs in which the changes are most frequently met 

 with are the lungs, heart, stomach, and intestines. 



If death occurs during the early stages, no marked 

 change may be found anywhere, though in some instances 

 the lungs are slightly paler, and have greater buoyancy 

 when floated in water than normal pulmonary tissue. 



When the disease has existed for a long time, the usual 

 pathological lesions which may be found in the lungs are 

 interlobular and vesicular emphysema, thickening of the 



