DISEASES OF THE RESPIRATORY 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. 
Symptoms.—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 unless 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. Round-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 
