40 DISEASES OF THE AIR-PASSAGES. 



jaw. And when there is the least suspicion that the cough 

 is kept up through any source of irritation within the thorax, 

 a rowel may be insinuated in the breast ; for with this 

 counter-irritation I have known medicine to succeed, when, 

 without such collateral aid, it has failed. The medicine best 

 adapted for a case of this latter description is, after clearing 

 out the bowels and setting the digestive organs to rights, the 

 camphor and squill ball 1 have just prescribed ; or, that fail- 

 ing, the belladonna ball may be tried. When both fail, a 

 course of mercury may be recommended. Keeping the 

 horse quiet in his stable is indispensable. 



ROARING. 



Roaring is no more a disease in horses than crying is in 

 ourselves. It is but a symptom, and of itself so vague a one, 

 that, without much careful investigation, it is often as diffi- 

 cult to say what disease or disorder is giving rise to it as 

 to divine the cause of a person^s grief. 



Definition. — Roaring may be defined to be, breathing 

 with a loud and unnatural sound, under exertion of any kind. 



The sound or noise emitted varies under different unna- 

 tural conditions of the air-passages, and also imder different 

 degrees of exertion to which the animal may be put. With 

 a view of elucidating the first of these assertions, I shall re- 

 late an experiment I made some years ago, touching the 

 constriction of the windpipe. The second assertion rests 

 upon facts known, I believe, to most experienced horse- 

 men; viz. that roarers made to gallop very fast become 

 whistlers : and, pushed to their utmost speed, lose even 

 their whistling noise. These varieties in the sound or 

 " roar,^^ have given rise among horse-people to the epithets, 

 " grunters,^^ '^ wheezers," " whistlers,^^ '^ high-blowers," 

 " trumpeters," &c. The experiment I made is this : 



I passed a ligature of broad tape around the windpipe 

 at about one-third of its length down the neck from the head. 

 The tape was at first drawn only moderately tight, and the 

 animal roared when made to trot. Next, tlie pipe was com- 

 pressed to about half its natural caliber : the animal then 



