w the pin. The
ring is then erected to the position shown dotted at M, by moving the
handle, H, downward to L and locking it there with the latch, Z. The
fork, A, is then inserted and, engaging the pin at the spring loop, K,
the pin is pushed into the ring, thus closing the pin. Slight rotation
of the pin with the forceps may be necessary to get the point into the
keeper. The upper instrument is sometimes useful as a mechanical spoon
for removing large, smooth foreign bodies from the esophagus.]

_Esophageal Dilators_.--The dilatation of cicatricial stenosis of the
esophagus can be done safely only by endoscopic methods. Blind
esophageal bouginage is highly dangerous, for the lumen of the
stricture is usually eccentric and the bougie is therefore apt to
perforate the wall rather than find the small opening. Often there is
present a pouching of the esophagus above a stricture, in which the
bougie may lodge and perforate. Bougies should be introduced under
visual guidance through the esophagoscope, which is so placed that the
lumen of the stricture is in the center of the endoscopic field. The
author's endoscopic bougies (Fig. 40) are made with a flexible
silk-woven tip securely fastened to a steel shaft. This shaft lends
rigidity to the instrument sufficient to permit its accurate
placement, and its small size permits the eye to keep the silk-woven
tip in view. These endoscopic bougies are made in sizes from 8 to 40,
French scale. The larger sizes are used especially for the dilatation
of laryngeal and tracheal stenoses. For the latter work it is
essential that the bougies be inspected carefully before they are
used, for should a defective tip come off while in the lower air
passages a difficult foreign body problem would be created.
Soft-rubber retrograde dilators to be drawn upward from the stomach by
a swallowed string are useful in gastrostomized cases (Fig. 35).

[FIG 38.--Half curved hook, 45 cm. and 60 cm. Full curved patterns are
made but caution is necessary to avoid them becoming anchored in the
bronchi. Spiral forms avoid this. The author makes for himself steel
probe-pointed rods out of which he bends hooks of any desired shape.
The rod is held in a pin-vise to facilitate bending of the point,
after heating in an alcohol or bunsen flame.]

_Hooks_.--No hook greater than a right angle should be used through
endoscopic tubes; for should it become caught in some of the smaller
bronchi its extraction might res