64 Roaring in Horses. 



It may be remarked that, in all cases of Eoaring, and 

 particularly those in an advanced stage, the stertorous or 

 stridulous noise can be greatly lessened, and the distress 

 the horse exhibits during exertion apparently relieved, by 

 diminishing the volume of air entering the nostrils, a fact 

 which can be demonstrated by partially occluding these by 

 the hand. This has been taken advantage of by those who 

 desired to utilize horses otherwise unserviceable, who have 

 devised an apparatus to fit over the nose, which prevents 

 the dilatation of the nostrils beyond a certain degree. 



In all cases of bad Roaring, there is an expiratory sound 

 much louder than that of normal respiration, but, of course, 

 much less marked than the characteristic inspiratory one. 

 This is produced partly by the larynx and partly by the 

 nostrils, and corresponds, in the comparison made as to the 

 resemblance of the sound to sawing wood or filing steel, to 

 the drawing-back sound of the saw or file in order to make 

 another cut. 



2. Dyspncea. 



With regard to the amount of difficulty in breathing, 

 this will depend upon the stage the disease has reached. In 

 slight cases there may be little, if any, difficulty observed, 

 and the animal's utility may not be impaired to any appre- 

 ciable degree, the unnatural sound alone forming an objec- 

 tion; and even when the noise is somewhat loud, the animal 

 may yet be capable of undergoing a considerable amount 

 of active exertion for a long time. But it may be accepted 

 as the rule, that the amount of obstruction to the breath- 

 ing, and therefore the degree of distress the horse must 

 suffer, is related to the intensity and quality of the sound. 



The obstruction to the entrance of air to the lun^fs durinof 

 exertion, leads to longer and more energetic inspiratory 

 efforts, in order to obtain sufficient for the increased demands 

 of the body, and also necessitates more hurried expiratory 

 endeavours to compensate for the delay. In advanced cases, 



