482 OPEBATIONS ON THE EESPIBATOKY APPARATUS. 



Fig. 425.— Vaoliette's Tube. 



Pig. 426.— Tube of Pradat. 



Fig. 427.— Tube of Brogniez. 



the first being the the exposure of the trachea ; of the second, to 

 open it by removing a circular portion of the organ ; and the 

 third by the introduction of the tube into the aperture prepared 

 for it. 



