e older tubes, with the supposed function of allowing partial
breathing through the larynx, is a most pernicious thing. A properly
fitted tube should not take up more than half of the cross section of
the trachea, and should allow the passage of sufficient air for free
laryngeal breathing when it is completely corked. The fenestrum is,
moreover, rarely so situated that air can pass through it; the
fenestral edges act as a constant irritant to the wound, producing
bleeding and granulation tissue.

[FIG. 103.--Schema showing thick pad of gauze dressing, filling the
space, A, and used to hold out the author's full-curved cannula when
too long, prior to reactionary swelling, and after subsidence of the
latter. At the right is shown the manner in which the ordinary cannula
of the shops permits a patient to asphyxiate, though some air is heard
passing through the tracheal opening, H, after the cannula has been
partially withdrawn by swelling of the tissues, T.]

[FIG. 104.--The author's tracheotomic cannulae. A, shows cane-shaped
cannula for use in intrathoracic compressive or other stenoses. B,
shows full curved cannula for regular use. Pilots are made to fit the
outer cannula; the inner cannula not being inserted until after
withdrawal of the pilot.]

_Anesthesia_.--No dyspneic patient should be given a general
anesthetic; because any patient dyspneic enough to need a tracheotomy
for dyspnea is depending largely upon the action of the accessory
respiratory muscles. When this action is stopped by beginning
unconsciousness, respiration ceases. If the trachea is not immediately
opened, artificial respiration instituted, and oxygen insufflated, the
patient dies on the table. Skin infiltration along the line of
incision with a very weak cocaine solution (1/10 of 1 per cent),
apothesine (2 per cent), novocaine, Schleich's fluid or other local
anesthetic, suffices to render the operation painless. The deeper
structures have little sensation and do not require infiltration. It
has been advocated that an interannular injection of cocaine solution
with a hypodermic syringe be done just prior to incision of the
trachea for the purpose of preventing cough after the incision of the
trachea and the insertion of the cannula. It would seem, however, that
this introduces the risk of aspiration pneumonia and pulmonary
abscess, by permitting the aspiration and clotting of blood in small
bronchi, followed by subsequent breaking down of the