DISEASES OF THE EESPIEATOEY ORGANS. 129 



first. In this variety the air finds its way into the lung tissue be- 

 tween the air cells or the tissue between the small lobules. 



Syniftoms. — Almost every experienced horseman is able to detect 

 heaves. The peculiar movement of the flanks and abdomen point out 

 the ailment at once. In recent cases, however, the affected animal 

 does not always exhibit the characteristic breathing imless exerted 

 to a certain extent. The cough which accompanies this disease is 

 peculiar to it. It is difficult to describe, but the sound is short and 

 something like a grunt. When air is inspired — that is, taken in — it- 

 appears to be done in the same manner as in health ; it may possibly 

 be done a little quicker than natural, but not enough to attract any 

 notice. It is when the act of expiration (or expelling the air from 

 the lungs) is performed that the great change in the breathing is 

 perceptible. It must be remembered that the lungs have lost much 

 of their elasticity, and in consequence of their power or contracting' 

 on account of the degeneration of the walls of the air cells, and' also 

 on account of the paralysis of muscular tissue before mentioned. 

 The air passes into them freely, but the power to expel it is lost to 

 a great extent by the lungs; therefore the abdominal muscles are 

 brought into play. These muscles, especially in the region of the 

 flank, are seen to contract, then pause for a moment, then complete 

 the act of contracting, thus making a double bellowslike movement 

 at each expiration, a sort of jerky motion with every breath. The 

 double expiratory movement may also be detected by allowing the 

 horse to exhale against the face or back of the hand. It will be ob- 

 served that the expiratory current is not continuous, but is broken 

 into two jets. When the animal is exerted a wheeezing noise accom- 

 panies the breathing. This noise may be heard to a less extent when 

 the animal is at rest if the ear is applied to the chest. 



As before remarked, indigestion is often present in these cases. 

 The animal may have a depraved appetite, as shown by a desire to 

 eat dirt and soiled bedding, which he often devours in preferencce 

 to the clean feed in the trough or manger. The stomach is liable 

 to be overloaded with indigestible feed. The abdomen may assume 

 that form called "potbellied." The animal frequently passes wind 

 of a very offensive odor. When first put to work dung is passed 

 frequently; the bowels are often loose. The animal can not Stand 

 much work, as the muscular system is soft. Eound-chested horses 

 are said to be predisposed to the disease, and it is certain that in 

 cases of long standing the chest usually becomes rounder than natural. 



Certain individuals become very expert in managing a horse af- 

 fected with heaves in suppressing the symptoms for a short time. 

 They take advantage of the fact that the breathing is much easier 

 when the stomach and intestines are empty. They also resort to the 

 36444°— 16 — -9 



