142 Roaring in Horses. 



Removal of the obstruction was sought to be obtained 

 with as little mutilation as possible, and it was resolved to 

 proceed step by step until it was ascertained what, and how 

 much, it was necessary to excise in order to enable the 

 respiration to be carried on noiselessly and with ease. 



The left vocal cord (Fig. 9, g) was extirpated through an 

 opening made in the middle crico- thyroid ligament, between 

 the wings of the thyroid cartilage. This was not found satis- 

 factory, so far as the noise was concerned, and the excision 

 was then extended to the anterior portion of the arytsenoid 

 cartilage (lorocessus vocalis. Fig. 9, i toj, black dotted lines). 

 For about a month, two horses operated on in this manner 

 made no noise, but whether from being put to severe 

 exertion too soon, from exuberant granulations springing 

 up in the laryngeal wound, or from the remaining portion 

 of the arytsenoid cartilage falling deeper into the aditus, 

 the Roaring reappeared, though the distress in breathing 

 was removed. A portion of the vocal cord and the greater 

 part of the arytsenoid cartilage (Fig. 9, h to g, light dotted line), 

 were next removed ; but with no better results, so far as the 

 Roaring was concerned, the chief trouble being the extra- 

 ordinary tendency of the remaining cartilage to rapidly 

 throw out luxuriant granulations of great density, and 

 which occupied almost more space in the cavity than did 

 the parts that were removed. 



Next the upper portion of the cartilage was excised (Fig. 

 9, I g k), but this also was unsatisfactory. 



Then it was decided to excise the whole of the left 

 aryt?enoid cartilage ; this, in causing close adhesion of the 

 vocal cord, and consequent obliteration of the laryngeal sac, 

 by which the larynx Avould be completely cleared of the 

 obstruction, must, it was surmised, allow ample space for 

 a full volume of air ; while, no fragment of cartilage being 

 left, troublesome granulations were not so likely to interrupt 

 the healing process. The experience gained in the previous 

 operations showed that there could be little danger in this 



