g readily when
sponged. The Wassermann reaction may contribute to the diagnosis; but
if negative, a thorough and prolonged test with mercury is imperative.
It must be remembered that a person with lues may have a simple,
mixed, or malignant ulceration of the esophagus, or the three lesions
may even be combined. It may be in some cases possible to demonstrate
the treponema pallidum in scrapings taken from the ulcer.

The single _tuberculous ulcer_ is usually pale, superficial, and
granular in base. If it is a continuation from more extensive
extra-esophageal tuberculous ulceration, pale cauliflower granulations
may be present. Slight cicatrices may be seen. Tuberculosis in other
organs can almost always be demonstrated by roentgenographic,
physical, or laboratory studies. Tuberculin tests and animal injection
with an emulsion of a specimen of tissue may be required. The specimen
must be taken very superficially to avoid risk of perforation.

_Sarcomatous ulcers_ do not differ materially in appearance from those
of carcinoma, but they are much more rare.

_Carcinomatous ulcer_ is usually characterized by the very vascular
bright red zone, raised edges, fungations, granulation tissue that
bleeds freely on the lightest touch, and above all, it is almost
invariably situated on an infiltrated base which communicates a
feeling of hardness to the pressure of sponges or the esophagoscope
itself. A scar may be from the healing of an ulcer from stasis, or one
of specific or precancerous character. It may be a cancerous process
developing on the site of a scar, so that the presence of scar tissue
does not absolutely negative malignancy. As a rule, however, scars are
absent in cancer of the esophagus. The firm and sometimes prominent
ridge of the crossing of the left bronchus must not be mistaken for
infiltration, and the esophagoscopist must be familiar with the normal
rigidity of the cricopharyngeus.

[242] Mixed infection gives to all esophageal ulceration a certain
uniformity of appearance, so that laboratory studies of smears or
histologic and bacteriologic study of tissue specimens taken from
fungations or thickened edges are often required to confirm the
endoscopic diagnosis. If the edges are thin and flat, the taking of a
specimen involves some risk; fungations can be removed without risk;
so can nodules, but care must be taken that projecting folds are not
mistaken for nodules. It is always wise to push the therapeutic