ROARING. 255 



difficulty. The upper air-passages, perhaps those of the head, did not corres- 

 pond with his unusually capacious chest ; yet he was never beaten. It is said 

 that he never met with an antagonist fairly to put him to the top of his speed, 

 and that the actual effect of this disproportion in the two extremities of the 

 respiratory apparatus was not thoroughly tested. Mares comparatively seldom 

 become roarers. It appears to be difficult, if not impossible, to assign any 

 satisfactory reason for this ; but the fact is too notorious among horsemen to 

 admit of doubt. 



Roaring proceeds from obstruction in some portion of the respiratory canal 

 and oftenest in the larynx, for there is least room to spare — that cartilaginous box 

 being occupied by the mechanism of the voice : next in frequency it is in the 

 trachea, but, in fact, obstruction any where will produce it. Mr. Blaine 

 quoting from a French journalist, says, that a piece of riband lodged within 

 one of the nasal fossse produced roaring, and that even the displacement of a 

 molar tooth has been the supposed cause of it. Polypi in the nostrils have 

 been accompanied by it. Mr. Sewell found, as an evident cause of roaring, an 

 exostosis between the two first ribs, and pressing upon the trachea ; and Mr. 

 Percivall goes farther, and says that his father repeatedly blistered and fired a 

 horse for bad roaring, and even performed the operation of tracheotomy, and at 

 length the roaring being so loud when the horse was led out of the stable, that 

 it was painful to hear it — the poor animal was destroyed. No thickening of 

 the membrane was found, no disease of the larynx or trachea ; but the lungs 

 were hepatized throughout the greater part of their substance, and many of the 

 smaller divisions of the bronchi were so compressed, that they were hardly 

 pervious. 



Bands of Coagulated Lymph. — A frequent cause of roaring is bands of coagu- 

 lated lymph, morbidly viscid and tenacious, adhering firmly on one side, and 

 by some act of coughing brought into contact with and adhering to the other 

 side, and becoming gradually organized. At other times there have been rings 

 of coagulated lymph adhering to the lining of the trachea, but not organized. 

 In either case they form a mechanical obstruction, and will account for the 

 roaring noise produced by the air rushing violently through the diminished 

 calibre, in hurried respiration. Thickening of the membrane is a more fre- 

 quent cause of roaring than the transverse bands of coagulated lymph. In 

 many morbid specimens it is double or treble its natural thickness, and covered 

 with manifold ulcerations. This is particularly annoying in the upper part 

 of the windpipe, where the passages, in their natural state, are narrow. Thus 

 it is that roaring is the occasional consequence of strangles and catarrh, and 

 other affections of the superior passages. 



There is scarcely a horse of five or six years old who has not a portion of the 

 thyroid cartilage ossified. In some cases the greater part of the cartilages are 

 becoming bony, or sufficiently so to weaken or destroy their elastic power, and 

 consequently to render it impossible for them to be freely and fully acted upon 

 by the delicate muscles of the larynx. 



Chronic cough occasionally terminates in roaring. Some have imagined thai 

 the dealers' habit of coughing the horse, i. e. pressing upon the larynx to mako 

 him cough, in order that they may judge of the state of his wind by the sound 

 that is emitted, has produced inflammation about the larynx, which has termi- 

 nated in roaring, or assisted in producing it. That pain is given to the animal 

 by the rough and violent way in which the object is sometimes attempted to be 

 accomplished, is evident enough, and this must, in process of time, lead to mis- 

 chief; but sufficient inflammation and subsequent ossification of the cartilages 

 would scarcely be produced, to be a cause of roaring. 



The Disease of Draught-Horses generally. — There can be ho doubt of the 



