200 
TRACHEOTOMY TUBES OR CANULyE. 
too far forward, as the tube is then liable to fall out during coughing or violent 
expiratory movements. Barthelemy’s tube somewhat disfigures the animal; 
expectoration of mucous, pus, or blood is rendered more difficult; and where 
Fig. 91.—Leblanc’s jointed canula. 
used for long periods very careful fitting is necessary to prevent thickening 
and narrowing of the trachea. This tube is therefore now seldom used. To 
overcome the above disadvantages models have been designed by Leblanc, 
Degive, Vachetta, Peuch, Field, Coleman, Jones, and others. Doing 
Fig. 92.—Leblanc’s jointed canula. 
away with the straps lessens disfigurement without interfering with the 
secure fixing of the canula, and diminishes risk of bruising and irritation. 
The trachea remains unobstructed in an upward direction as far as the larynx, 
whilst the canula is very easily cleaned. Leblanc has constructed a jointed 
tube said to be adapted to every form of neck (figs. 91 and 92), but one of the 
halves sometimes becomes detached and drops into the trachea. Modern 
