DANGERS OF TRACHEOTOMY. 



459 



(tracheal stenosis). Induration occasionally occurs in the skin 

 and the soft tissues lying beneath, and usually follows cellulitis. 

 Proliferation producing tracheal stenosis results from faulty forma- 

 tion of the cannula, from its being too heavy, badly made, or not 



Fig. 365. — Superior orifice of the larynx and glottis of a horse affected with 

 chronic roaring. 



fitting the form of the neck. The cannula. cannot fit well if it be too 

 long, too narrow, too little, or too much bent, or if the opening in 

 the trachea be too large. A pronounced tendency to such growths 

 often exists in heavy horses, and though the cannula is perfect in 

 every respect, the contraction recurs after each operation. Such 

 stenosis gradually renders the introduction of the tube more and 

 more difficult, and finally impossible. The tracheal opening must 



