344 ROARING. 



ments, produces sounds modulated according to its figure, 

 extent, and the precise locality where the opposition 

 is situated, which horsemen call wheezing, whistliny, roar- 

 ing, S)'c. ; terms sufficiently expressive. A horse wheezes 

 w^hen any obstruction is offered to the passage of air within 

 the nostrils ; he whistles when the foreign body is situated 

 in the hind part of the nostrils, or is but slight, and is 

 located near to the opening of the larynx ; but he roars 

 when the larynx is malformed, or hindrance is offered to 

 the free current of air within the windpipe. 



The causes of roaring are remote and proximate. The 

 chronic causes are mostly inflammation in the tracheal tube 

 itself. Occasionally it is brought on by the effects of in- 

 flammation on other parts ; as by the swelling and conse- 

 quent pressure of the salivary glands in strangles, or of those 

 abscesses which not unfrequently occur in violent catarrh in 

 the vicinage of" the pharynx. Obstructions accidentally 

 formed by exostoses, cicatrizations, &c., or extraneous sub- 

 stances lodged in the interior of the trachea, may any of 

 them occasion it. The acute causes might, with propriety, 

 include these accidental obstructions, but they are mainly 

 to be looked for in an extravasation, partial or extensive, of 

 coagulable lymph ; which, becoming organized, forms a per- 

 manent obstruction. When it is extensively spread over 

 the larynx, it produces whistling ; when it constringes the 

 rima glottidis, a whistling sound is the consequence, and is 

 often heard in our own respirations under catarrh ; or in the 

 ordinary respirations of some asthmatic persons. Whoever 

 has handled the throats of many old horses, must have ob- 

 served a hardened state of the larynx, which almost resisted 

 all attempts to what is termed " cough them." This ossi- 

 fication of the laryngeal cartilages is not an uncommon 

 cause ; and a similar state in the cartilages of the trachea is 

 productive of it also. A cause also of roaring is a band of 

 lymph stretched across the tracheal tube ; at others, an 

 internal ring of the same matter simply diminishes its 

 diameter. The obstruction is sometimes so considerable 

 as to excite the sound upon the slightest exertion ; in 

 general cases, however, roaring is only exerted when forcible 

 inspirations and expirations are made ; for it is, we believe, 

 equally produced by the one as by the other. Mechanical 



