688 OPEKATIONS. 



is self-suggestive. Some authorities however state that aluminium 

 is objectionable on account of its irritating the tissues with which 

 it comes in contact. I regret that I am unable to decide this 

 point. (2) It should, if of metal, as recommended by the late 

 Mr. F. B. Jones, be made of only one kind of metal, so that no gal- 

 vanic action be set ujo. (3) Evidently it should be of comparatively 

 large calibre. (4) There should exist as little difference as practic- 

 able between the calibre of the opening in the windpipe and that of 

 the tube, so that efficiency may be obtained with a minimum 

 amount of damage to the windpipe. (5) The tube should be 

 capable of being kept ojDen or shut, as may be required. (6) It 

 should remain securely in its place without requiring to be secured 

 by strings, tapes, etc. (7) It should be easy to insert and remove. 

 (8) It should offer as little imjDediment as possible to the passage 

 of air to and from the air-passage above the opening. (9) Its 

 mechanism should not be liable to get out of order, or to become 

 clogged up by the action of the discharge. (10) Its component 

 parts should have no tendency to become separated, or, in such 

 a case, to fall into the windpipe. (11) The body of the tube should 

 be of such a length that the shield can rest comfortably against 

 the skin, without the skin and muscles which cover the windpipe 

 being in any way compressed between the shield and the arms. Mr. 

 Jones, who had great experience in the application of tracheo- 

 tomy tubes, condemned the use of washers, which many place 

 between the shield and skin, when the swelling caused by the 

 operation has gone down. Their employment naturally interferes 

 with the cleanliness of the j^art, and can be dispensed Avith by 

 having two or three tubes of different lengths of body ; provided, 

 of course, that expense is no object. (12) The branches (arms) 

 should be of such a form and length that while giving free passage 

 to the air to and from the larynx, they will irritate the interior of 

 the windpipe as little as possible. The larger the arms, other 

 things being equal, the more liable are they to cause inflammation 

 and ulceration of the interior of the windpipe. 



CHOICE OF A TUBE.— Among English permanent tubes, that 

 of Jones, and among Continental ones, that of Peuch (in aluminium) 

 appear to be the best. Leblanc's tube has the advantage that its 

 shield can be shifted either backwards or forwards on its body, 

 so that, with it, there is no need to use washers to fill up the space 

 between the skin and the shield, when the swelling caused by the 

 operation subsides. Field's tube is a very good one for temporary 

 use. 



SITE OF OPENING. — For permanent tracheotomy, there are 

 three conditions which regulate the iDOsition of the opening in the 



