202 
TRACHEOTOMY TUBES OR CANUTE. 
Coleman s tube is also to be recommended as light, simple, and convenient. 
The paits are very firmly united when the tube is in position, and there is 
less danger of their being displaced by the patient than in the case of 
Field’s tube. 
Canulse must be light and durable, and their edges, as already stated, well 
Fig. 95,—Coleman’s tracheotomy tube. 
rounded off. They are usually made of German silver, but their weight may 
be 1 educed by using aluminium, which has been employed m making canulse 
on Peuch’s model. These seem to be well suited for race-horses. Where it 
Fig. 96,—Double-tube canula. 
is necessary to combat suffocation occurring in diseases of an infectious 
character, a canula of a long form is selected, in order to avoid bruising the 
swollen soft parts in the neighbourhood of the point of operation. In anticipa¬ 
tion of swelling supervening, the steadying of the canula may be effected by 
placing one or more leather shields below the plate, or enveloping the projecting 
portion of the tube in jute^or tow. 
