14 Roaring in Horses. 



asserts that he never witnessed an exception to the rule ; 

 he always found the muscles on the left side of the larynx 

 and the left recurrent nerve in an advanced stage of 

 atrophy. Professor Trasbot, of the same school, stated in 

 1879 that from the time his colleague, Goubaux, had 

 drawn attention to the subject, up to that date, whenever 

 the opportunity occurred he had examined, post-mortem, the 

 larynx of every horse brought to the school and known to 

 have been a Roarer during life, and always with the same 

 result — the discovery of wasting of the muscles on the left 

 side of that organ. i 



In a work on the muscles of the horse, published by 

 Professor Gunther in 1866, it is mentioned that ninety-six 

 per cent, of horses affected with " chronic Roaring " have 

 wasting of the left laryngeal muscles, and that it is 

 extremely rare to find those on the right side involved.^ 

 Bruckmliller, in his Text-Book of Pathological Zootomy, 

 published in 1869, alludes to Roaring being due, among 

 other causes, to atrophy of the dilator muscle of one side 

 of the larynx : and though he agreed with Gunther that 

 an alteration (degeneration) in the nerve supplying it would 

 produce such wasting, yet his observations led him to 

 believe that degeneration of the nerve was not always the 

 cause, but that the muscle weakness might result from 

 induration after inflammation of its texture, induced by 

 mechanical action.^ 



Other writers have confirmed these observations, though 

 opinions have been far from unanimous as to the pathology 

 of the morbid conditions which occasion the impeded 

 respiration; and even the immediate cause of the noise 

 itself has been much discussed, and is not yet definitely 

 decided upon. 



^ "Archives Ycterinaire," 1870. 



2 " Die Topographische Myologie des Pferdes," Hanover, 188G. 



3 " Lehrbuch der Pathologischen Zootomie der Hausthiere," Vienna, 

 1869. 



