itrate--3 lbs.
Water--5 gal.

Boil until arsenic is dissolved. When cold add:
Carbolic acid 1500 c.c.
Glycerin 1250 c.c.
Alcohol (95%) 1250 c.c.

For each body use about 3 gal. of fluid.

The method of introduction of the endoscopic tube, and its various
positions can be demonstrated and repeatedly practiced on the cadaver
until a perfected technic is developed in both the operator and
assistant who holds the head, and the one who passes the instruments
to the operator. In no other manner can the landmarks and endoscopic
anatomy be studied so thoroughly and practically, and in no other way
can the pupil be taught to avoid killing his patient. The
danger-points in esophagoscopy are not demonstrable on the living
without actually incurring mortality. Laryngeal growths may be
simulated, foreign body problems created and their mechanical
difficulties solved and practice work with the forceps and tube
perfected.

_Practice on the Rubber-tube Manikin_.--This must be carried out in
two ways.
1. General practice with all sorts of objects for the education of
the eye and the fingers.
2. Before undertaking a foreign body case, practice should be had
with a duplicate of the foreign body.

It is not possible to have a cadaver for daily practice, but
fortunately the eye and fingers may be trained quite as effectually by
simulating foreign body conditions in a small red rubber tube and
solving these mechanical problems with the bronchoscope and forceps.
The tubing may be placed on the desk and held by a small vise (Fig.
72) so that at odd moments during the day or evening the fascinating
work may be picked up and put aside without loss of time. Complicated
rubber manikins are of no value in the practice of introduction, and
foreign body problems can be equally well studied in a piece of rubber
tubing about 10 inches long. No endoscopist has enough practice on the
living subject, because the cases are too infrequent and furthermore
the tube is inserted for too short a space of time. Practice on the
rubber tube trains the eye to recognize objects and to gauge distance;
it develops the tactile sense so that a knowledge of the character of
the object grasped or the nature of the tissues palpated may be
acquired. Before attempting the removal of a particular foreign body
from a living patient, the anticipated problem should be simulated
with a duplicate of the foreign body in a rubber tube. In this way the