ROARING IN HORSES. 35 



first rings of the trachea.* But by doing 

 so, the operator is Hable to injure one of the 

 vocal cords, either during a movement of the 

 patient, incompletely anesthetised, or by intro- 

 ducing the instrument a little to one side of 

 the middle line, and thus taking an oblique 

 direction. To avoid this accident it is neces- 

 sary to act in the following way. The 

 bistoury held in a vertical position with the 

 cutting edge behind is passed into the crico- 

 thyroidean ligament immediately in front of 

 the cricoid cartilage, then this cartilage, the 

 crico-tracheal, and the two first rings of the 

 trachea are incised, then the lips of the 

 laryngo-tracheal incision are withdrawn from 

 one another by tenacula, or by spring hooks, 



* The incision need only be extended to the first ring 

 of the trachea, provided the canula is not employed, or 

 only used at the moment of dressing the wound. 



