JOINTED TRACHEOTOMY TUBES. 
201 
experience shows that the tracheal tubes of Field, Peuch Jones and Coleman, 
which correspond in principle, are amongst the best (tigs. 93 to 95). lliey con¬ 
sist of two or three pieces, which are inserted singly by first pushing the wider 
tube into the trachea and afterwards the narrower one, so that the projections 
point upwards and downwards in the lumen of the trachea without pressing 
on its mucous membrane. Provided it is sufficiently long to enter easily, the 
tube with the shortest projections is to be preferred, because its hold is more 
Fm. 93.—Pencil’s canula. 
secure and it is less liable to injure the posterior wall of the trachea. 
the length of the canula, that is, the distance between the plate and t 
curvature of the projections, must correspond to the thickness of the anteno 
wall of the neck. Such tubes may be worn by horses for several years wi iou 
Fig. 94-—Field’s tracheotomy tube. 
nrodueing stenosis or difficulty in application. Hauptner has recently some¬ 
what modified Peuch’s tube. The inner portion is made lighter and can be 
• ivrrrlnpprl • hut on the other hand, it has not so wide a basis, 
1—»«. To .,..,0.1,0, .1,, ,,1,= 
the ’index finger of the left hand should first be passed into the trachea, 
whet the tube itself may easily be slid along it, the finger acting as a guide. 
Af S r s d8 tube e and is convenient to insert and 
withdraw as well as to clean. The shields and half tubes should, howevei, lie 
either in one piece or be very securely united in order to prevent accidents. 
