RESPIRATORY AFFECTIONS 



genitors. Some peculiarity In the conformation 

 of the neck has been regarded as a predisposing 

 factor in the development of roaring. Certain 

 hunters become roarers quite early on in life, 

 others develop it later. As a rule the sound 

 is developed insidiously, but occasionally 

 it appears suddenly. It may be continuous, 

 or only of an intermittent nature. Intermittent 

 forms of roaring are the most deceptive, and 

 a veterinary surgeon examining a horse as to 

 soundness, might easily overlook such a defect, 

 in spite of the fact that he employed all reason- 

 able means at his disposal for its detection. 

 Needless to say, there would be no liability on his 

 part, on the ground of professional negligence. 



By far the commonest cause of roaring is that 

 in connection with the muscles of the larynx, 

 the fibres of which gradually undergo a patho- 

 logical change, known as fatty degeneration; 

 consequently, the muscles are no longer capable 

 of performing their normal functions. Impli- 

 cated in this diseased process is the motor branch 

 of the left recurrent nerve. It is the dilator 

 muscles of the larynx that are in a paralytic 

 state. Apart from this, as a cause of roaring, 



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