1$^ ON RESPIRATION, 



horses, when their pace is accelerated. A horse 

 of this description is termed a Roarer. From 

 my own observation, I have not been able to 

 discover whether its source is in the lungs, the 

 trachea, or the nose, though it is probable its 

 seat is in the trachea or larynx. Dealers have a 

 method of ascertaining the existence of the dis- 

 ease by striking the horse under the belly with a 

 whip, and turning him suddenly round at the 

 same time. If he groans during this process, 

 they say it proves that he is a roarer. This is 

 probably occasioned by the sudden contraction 

 of the abdominal muscles forcing air from the 

 lungs through the trachea with greater rapidity, 

 in consequence of the pain he feels from the 

 stroke of the whip, as well as from the bending 

 of the ribs in the action of turning round in a 

 small compass. This disease prevails to a dif- 

 ferent degree In different subjects; in its com- 

 mencement it is generally manifested by a 

 whistling noise, but in the confirmed state it is 

 more sonorous, and resembles deep groaning. 



In 



