TEACHEOTOMY. 



687 



bear such a grievous disfigurement as the employment of the tube 

 necessitates. As horses intended for the turf, whether on the flat 

 or over a country, are required to exert their powers to the utmost 

 only at comparatively long intervals, and during short spaces of 

 time ; permanent tracheotomy will generally succeed better with 

 them, than with other classes of horses, if the precaution be ob- 

 served of opening the tube only when they are being run, or during 

 fast training gallops. In fact, some trainers of tube-bearing horses 

 consider, as a result of their experience, that it is best not to open 

 the tube, except of course for cleaning purposes, during training. 



Jones' tracheotomy tube. 



As observed by Moller, coarse-bred horses are more liable, from 

 the use of the tracheotomy tube, to inconvenient, if not dangerous, 

 diminution of the calibre of the windpipe from thickening of the 

 mucous membrane and its underlying tissues, than thorough-breds. 



TRACHEOTOMY TUBES.— The tubes most commonly employed 

 consist of a " shield," which remains outside the opening ; a body, 

 which is in the form of a cylinder, and which rests in the opening 

 of the windpipe ; and an upper and lower branch (or arm), which 

 prevents the tube from falling out. 



The chief requirements in a tracheotomy tube are as follows : — 

 (1) It should be as light as practicable. Here, the use of aluminium 



