sion of syphilis
when it appears on parts of the body other than the genitals. It differs
in some respects from the hard chancre as met with on the penis; it is
usually larger, the induration is more diffused, and the enlarged glands
are softer and more sensitive. The glands in nearest relation to the
sore are those first affected, for example, the epitrochlear or axillary
glands in chancre of the finger; the submaxillary glands in chancre of
the lip or mouth; or the pre-auricular gland in chancre of the eyelid or
forehead. In consequence of their divergence from the typical chancre,
and of their being often met with in persons who, from age,
surroundings, or moral character, are unlikely subjects of venereal
disease, the true nature of erratic chancres is often overlooked until
the persistence of the lesion, its want of resemblance to anything else,
or the onset of constitutional symptoms, determines the diagnosis of
syphilis. A solitary, indolent sore occurring on the lip, eyelid,
finger, or nipple, which does not heal but tends to increase in size,
and is associated with induration and enlargement of the adjacent
glands, is most likely to be the primary lesion of syphilis.

[Illustration: FIG. 38.--Primary Lesion on Thumb, with Secondary
Eruption on Forearm.[1]]

[1] From _A System of Syphilis_, vol. ii., edited by D'Arcy Power and
J. Keogh Murphy, Oxford Medical Publications.

#The Soft Sore, Soft Chancre, or Chancroid.#--The differential diagnosis
of syphilis necessitates the consideration of the _soft sore_, _soft
chancre_, or _chancroid_, which is also a common form of venereal
disease, and is due to infection with a virulent pus-forming bacillus,
first described by Ducrey in 1889. Ducrey's bacillus occurs in the form
of minute oval rods measuring about 1.5 [micron] in length, which stain
readily with any basic aniline dye, but are quickly decolorised by
Gram's method. They are found mixed with other organisms in the purulent
discharge from the sore, and are chiefly arranged in small groups or in
short chains. Soft sores are always contracted by direct contact from
another individual, and the incubation period is a short one of from two
to five days. They are usually situated in the vicinity of the fraenum,
and, in women, about the labia minora or fourchette; they probably
originate in abrasions in these situations. They appear as pustules,
which are rapidly converted into small, acutely inflamed ulcers with
s