e optical apparatus should be inserted through the tube
only after the stomach has been entered. Blind insertion of a rigid
metallic tube into the esophagus is an extremely dangerous procedure.

The descriptions and illustrations of the stomach in anatomical works
must be disregarded as cadaveric. In the living body, the empty
stomach is usually found, on endoscopic inspection, to be a collapsed
tube of such shape as to fit whatever space is available at the
particular moment, with folds and rugae running in all directions, the
impression given as to form being strikingly like searching among a
mass of earth worms or boiled spaghetti. The color is pink, under
proper illumination, if no food is present. Poor illumination may make
the color appear deep crimson. If food is present, or has just been
regurgitated, the color is bright red. To appreciate the appearance of
gastritis, the eye must have been educated to the endoscopic
appearances under a degree of illumination always the same. The left
two-thirds of the stomach is most easily examined. The stomach wall
can be pushed by the tube into almost any position, and with the aid
of gentle external abdominal manipulation to draw over the pylorus it
is possible to examine directly almost all of the gastric walls except
the pyloric antrum, which is reachable in relatively few cases. A
lateral motion of from 10 to 17 cm. can be imparted to the
gastroscope, provided the diaphragmatic musculature is relaxed by deep
anesthesia. The stomach is explored by progressive traverse. That is,
after exploring down to the greater curvature, the tube-mouth is moved
laterally about 2 centimeters, and the withdrawing travel explores a
new field. Then a lateral movement affords a fresh field during the
next insertion. This is repeated until the entire explorable area has
been covered. Ballooning the stomach with air or oxygen is sometimes
helpful, but the distension fixes the stomach, lessens the mobility of
the arch of the diaphragm, and thus lessens the lateral range of
gastroscopic vision. Furthermore, ballooning pushes the gastric walls
far away from the reach of the tube-mouth. A window plug (Fig. 6) is
inserted into the ocular end of the gastroscope for the ballooning
procedure.

[275] Like many other valuable diagnostic means, gastroscopy is very
valuable in its positive findings. Negative results are entitled to
little weight except as to the explorable area.

The gastroscopist wor