History of Roaring. 11 



tortion of these tubes, hepatization of the hings, and spasm 

 of the muscles of the glottis. But he likewise mentions 

 wasting of the muscles on one side of the larynx as an 

 occasional cause. He says : " Some years have now- 

 elapsed since it was first discovered that the larynges of 

 Roarers occasionally presented us with the singular 

 phenomenon of the muscles on one side being wasted 

 away or absorbed, while on the other they appeared to 

 exhibit unusual volume and redness, and strength of fibre. 

 Since the first discovery, everyone almost has met with 

 cases of the kind ; but no person seems as yet to have 

 given an explanation of this new piece of pathology."^ 



Again he writes : " Another, and a not very uncommon 

 cause of Roaring, is a wasting, or, in some instances, a total 

 absorption of one or more of the small muscles of the 



larynx. I have lately examined a horse of Mr. ; a 



remarkable instance of it. In his larynx, upon the near 

 side, the crico-arytenoideus posticus was very pale, and 

 shrunk to half its original size ; the crico-arytenoideus 

 lateralis, the thyro-arytenoideus, and the arytenoideus, were 

 altogether colourless and scarcely recognisable as muscles ; 

 but their antagonists, upon the other side, were unusually 

 red and strong. Now, these muscles, contracting in pairs, 

 are all employed in dilating the glottis ; but, if one set act 

 by themselves, this orifice is not only distorted, but actually 

 diminished in dimension, in consequence of the arytenoid 

 cartilage of the opposite side being drawn over it. Thus it 

 is, then, that Roaring is here produced. How we are to 

 account for these changes — to what original cause refer 

 them — is as yet unknown. By some they are loosely spoken 

 of as the ultimate consequences of paralysis, or of spasm ; 

 but though these tales may satisfy their employers, they 

 are no more, to the profession, than the baseless conjectures 

 of their authors, and, as such, are deserving of no comment."^ 



1 "Lectures on the Veterinary Art," Part Second, p. 263. 



2 " Hippopathology,'' vol. ii., p. 44. 



