which their presence is causing. The germ of syphilis is no exception to
this rule. Its entry into the body is followed by a period in which
there is no external sign of its presence to warn the infected person
of what is coming. This period of quiescence between the moment of
infection with syphilis and the appearance of the first signs of the
disease in the form of the chancre may vary from a week to six weeks or
even two months or more, with an average of about two or three weeks.

In the length of the incubation period and the comparatively trifling
character of the early signs, the germ of syphilis betrays one of its
most dangerous characteristics. The germ of pneumonia, for example, may
be present on the surface of the body, in the mouth or elsewhere, for a
long time, but the moment it gets a real foothold, there is an immediate
and severe reaction, the body puts up a fight, and in ten days or so has
either lost or won. The germ of syphilis, on the other hand, secures its
place in the body without exciting very strenuous or wide-spread
opposition. The body does not come to its own defense so well as with a
more active enemy. The fitness of the germ of syphilis for
long-continued life in the body, and the difficulty of marshaling a
sufficient defense against it, is what makes it impossible to cure the
disease by any short and easy method.

+The First Sore or Chancre.+--The primary lesion, first sore or
chancre,[6] is the earliest sign of reaction which the body makes to the
presence of the growing germs of syphilis. This always develops at the
point where the germs entered the body. The incubation period ends with
the appearance of a small hard knot or lump under the skin, which may
remain relatively insignificant in some cases and in others grow to a
considerable size. Primary lesions show the greatest variety in their
appearance and degree of development. If the base of the knot widens and