Symptoms and Diagnosis of Chronic Roaring. 69 



in pronouncing as to the existence of this wasting. When 

 the horse's head is somewhat extended, the larynx is more 

 exposed, and the index-finger can then readily feel its pos- 

 terior (or superior) surface, which is formed by the wide 

 expansion of the cricoid cartilage and the dilator muscles 

 covering it. If the left muscle is wasted, this surface will 

 be found much flatter on that than on the right side. The 

 subsidence of the aryta3noid cartilage on the left side, which 

 is also a noticeable feature in the diseased larynx, may be 

 likewise ascertained in the same way. A slight amount of 

 pressure with the index-finger on the left arytoenoid carti- 

 lage, in the like manner, will cause a loud noise in respiration, 

 as if the animal were galloped ; but there is little, if any, 

 distress. This is not the case if the right aryta^noid is 

 pressed upon ; as then more pressure is needed to produce 

 a certain amount of noise, and symptoms of asphyxia are 

 quickly manifested, owing to the complete closure of the 

 glottis through the immobility of the left cartilage. 



These are the chief diagnostic signs of chronic Roaring, 

 and they should be sufiicient to establish the existence of 

 the morbid condition which occasions it. We cannot, as 

 in man, employ the patient's voice to aid us, neither can we 

 examine the larynx with the laryngoscope or manually per 

 orani, owing to the immense length and narrowness of the 

 horse's mouth, its powerful jaws, and the long obstructive 

 soft palate. It has been stated that in a case of Roaring, 

 Hertwig passed his hand through the mouth into the 

 larynx, and found the left vocal cord relaxed, the right one 

 being tense ; and Bassi is reported to have done the same. 

 But it must be admitted that, for the reasons given, the 

 attempt is attended with danger, and not at all likely to be 

 satisfactory. The interior of the larynx can be explored in a 

 thorough manner by opening the organ through the middle 

 crico-thyroid membrane, or the trachea immediately beneath 

 the cricoid cartilage, and illuminating it by means of artificial 

 liofht. Auscultation, also, after excitement or exertion, will 



