176 A STUDY OF FARM. ANIMALS 



easy to do so. Some forms are not clearly apparent until 

 well established. If the respiration is not good, this fault 

 is brought out in some form of work, such as trotting, 

 hauling a load, etc. In the sale markets, horses are hitched 

 to wagons with brakes, so that they may be required to 

 make quite an exertion in moving along. If a horse is lame, 

 or has bad wind, these defects may be seen when he is in 

 action. 



Heaves is an unsoundness or trouble of the lungs which 

 is brought on through dusty feed, bad ventilation, or indi- 

 gestion. Broken wind or asthma is apparently much the 

 same thing. When the horse expels wind from the chest, 

 he lacks the muscular contraction of the lungs that char- 

 acterizes the sound animal, and makes a wheezing noise, 

 which is sometimes very loud. 



Roaring is another disease in which the horse makes a 

 loud noise during breathing. The larynx is affected, but not 

 the lungs. This is caused by a paralysis of the nerves and 

 muscles of the parts, which results in the noise in breathing. 

 Roaring is manifested during exertion, yet a horse may be 

 a roarer and be driven some distance without making much 

 if any noise. The disease is one of progression, and grad- 

 ually becomes worse. Roaring had always been regarded 

 incurable until some years ago when Dr. Williams, of Cornell 

 University, discovered a method of operating by which it 

 might be cured. This is known as the Williams operation, 

 and it is now performed with success in America and 

 abroad. 



Spavin, commonly referred to as bone spavin, is usually 

 found on the inner side and in front of the hock joint. There 

 are three forms of spavins. 



(a) The high, or true, spavin, the more serious one. 



(b) The low, or jack, spavin, and 



(c) The blind spavin, which affects the joint surface, but 

 causes no enlargement. 



