h a
transformer, or a storage battery.

_Spectacles_.--If the operator has no refractive error he will need
two pairs of plane protective spectacles with very large "eyes." If
ametropic, corrective lenses are necessary, and duplicate spectacles
must be in charge of a nurse. For presbyopia two pairs of spectacles
for 40 cm. distance and 65 cm. distance must be at hand. Hook temple
frames should be used so that they can be easily changed and adjusted
by the nurse when the lenses become spattered. The spectacle nurse has
ready at all times the extra spectacles, cleaned and warmed in a pan
of heated water so that they will not be fogged by the patient's
breath, and she changes them without delay as often as they become
soiled. The operator should work with both eyes open and with his
right eye at the tube mouth. The operating room should be somewhat
darkened so as to facilitate the ignoring of the image in the left
eye; any lighting should be at the operator's back, and should be
insufficient to cause reflections from the inner surface of his
glasses.

[FIG. 40.--The author's endoscopic bougies. The end consists of a
flexible silk woven tip attached securely to a steel shank. Sizes 8 to
30 French catheter scale. A metallic form of this bougie is useful in
the trachea; but is not so safe for esophageal use.]

[FIG. 41.--The author's laryngeal bougie for the dilatation of
cicatricial laryngeal stenosis. Made in 10 sizes. The shaded triangle
shows the cross-section at the widest part.]

[FIG. 42.--The author's bronchoscopic and esophagoscopic table.]

[46] _Endoscopic Table_.--Any operating table may be used, but the
work is facilitated if a special table can be had which allows the
placing of the patient in all required positions. The table
illustrated in fig. 42 is so arranged that when the false top is drawn
forward on the railroad, the head piece drops and the patient is
placed in the correct (Boyce) position for esophagoscopy or
bronchoscopy, i.e., with the head and shoulders extending over the end
of the table. By means of the wheel the plane of the table may
be altered to any desired angle of inclination or height of head.

_Operating Room_.--All endoscopic procedures should be performed in a
somewhat darkened operating room where all the desired materials are
at hand. An endoscopic team consists of three persons: the operator,
the assistant who holds the head, and the instrument assistant.
Another person is req