96 
TRACHEOTOMY TUBE AND TROCAR. 
Fig- 2 (p. 95), thecanula, has at one extremity, D, a marginal rim 
to prevent the shield from being displaced or hinder it from sliding 
off during the periods of adjustment. The other extremity, E, is 
thinner ; and on one side of it is a slot or slit which allows the 
canula at this part to firmly grasp the stilette, thereby preventing 
any obstruction during the introduction of the instrument. 
Fig. 3. 
Fig. 3 represents the stilette when it is withdrawn. It is com- 
posed of ten pieces united by six link-joints. The use of these 
joints obviously is to permit the stilette to be inserted into and 
withdrawn from the canula ; which obviously could not, from the 
great curve of the tube, be accomplished if the blade were solid. 
The handle, G, is chequered, for the purpose of giving slippery 
hands a surer grasp ; and it is also inclined upwards about 25°, 
with the intention of affording the operator greater command over 
it during the time of its insertion. The end of the stilette, H, is 
triangular, having its edges sharp, but its point blunt. 
Such is a description of the three pieces which enter into the 
composition of Mr. Gowing’s tracheotomy tube and trocar, and 
which, when put together, present the following appearance : — 
Fig. 4. 
The veterinary surgeon who has resolved to use it:, in the first 
