450 SYMPTOMS OF DISEASE OF EESPIEATORY ORGANS. 



ultimately perfectly recover, and seem to depend upon the 

 non-perfecting of the healing or reparative process in tedious 

 recoveries succeeding previous catarrhal affections, (c) By far 

 the most common laryngeal lesion, however, which seems to 

 operate in the production of abnormal sounds — of roaring, 

 specially so called — is a peculiar atrophic and degenerative 

 condition of certain muscles of the larynx, notably the muscles 

 which pass between and attach the arytenoid to the cricoid 

 cartilages posteriorly. When these are free from disease, and 

 in the exercise of healthy functional activity, the aperture of 

 the larynx is maintained in a uniform and adequate condi- 

 tion ; when inactive from any cause, the opposite conditions 

 ensue : there is narrowing and alteration of form, attended with 

 modification of normal sound during the performance of the 

 respiratory act. 



The morbid condition usually existing in connection with 

 these muscles, in cases of roaring, is that of atrophy and fatty 

 degeneration ; by this their power of action or contractility is 

 destroyed, and the more movable parts of the larynx, the 

 arytenoid cartilages, to which they are attached, approach 

 each other, by which the external opening of the larynx is 

 narrowed, and the edges of one or both cartilages brought into 

 the air-current in its passage to and from the trachea. 



Although it is not uncommon to meet with this degenerative 

 change affecting the greater number of the muscles of one side 

 of the larynx, or even certain of both sides, it is more frequently 

 confined to those of the left side only, or at least in a more 

 marked degree than the other. 



What may be the primary or direct cause of this disease of 

 nutrition affecting a particular group or groups of muscles, or 

 why those of the left side should be so frequently diseased as 

 compared with the right, are questions of great difficulty, upon 

 which it is easier to speculate than to offer a satisfactory reply. 

 By some this particular lesion, inducing abnormal respiration, 

 has been attributed to manipulatory interference. Endeavour- 

 ing, by means of reining, to give to the head an unnatural 

 position, by which the larynx, as a whole, is distorted, the 

 muscles thrown out of action, thereby inducing atrophic 

 changes. That such treatment may in certain instances induce 

 disease in the parts operated upon, resulting in defective respi- 



