EOARING. 281 



pressure upon the trunk of the nerve or from from dividing it, 

 will produce paralysis of the larjnageal muscles, and -passive 

 closure of the glottis, and roaring as a consequence of the 

 latter ; so that here we have examples of states of the larynx 

 of a nature the very opposite to each other, producing effects 

 precisely similar. 



V. — Stricture of one or both nasal passages. Mr. James 

 Turner, an eminent veterinary surgeon, relates a very 

 instructive case of this kind in the Veterinarian for 184I9, 

 pp. 14 and 15. 



yi. — Thickening of the mucous membrane of the larynx 

 is sometimes a cause of Eoaring ; more frequently, however, 

 it causes a roughness, or wheezing in the breathing. 



YII. — Curvature and ossification of the windpipe arising 

 from tightly reining up the head. This is not a common 

 cause, especially now that bearing reins have gone so much 

 out of use. 



YIII. — Ulceration of the mucous membrane and other 

 tissues of the larynx. This is not a common cause. Atrophy 

 of the muscles of one half of the larynx is perhaps of all 

 other causes the most common. 



Affectioi^s allied to EoAEiNG. — There are other affec- 

 tions of a nature closely allied to Eoaring, these are — Wheezing, 

 Piping or "Whistling, Grimtiug, and High Blowing. 



Wheezing is a peculiar roughness accompanying the breath- 

 ing in numbers of horses which have previously suffered from 

 an inflammatory affection of the larynx. It is rarely heard, 



