per cent had
neither. (Survey, March 25, 1916, Vol. 35, p. 749.)

+Concealed Syphilis and Medical Examinations of Prostitutes.+--A number
of delusions center around the relation of open and secret prostitution
to disease. From the description of syphilis given in the foregoing
pages, it must be apparent how little reliance can be placed, for
example, on the ordinary medical examination of prostitutes as practised
in segregated districts. The difficulties of efficient examination are
enormous, especially in women. Even with the best facilities and a high
degree of personal skill, with plenty of time and laboratory help in
addition, extremely contagious syphilis can escape observation entirely,
and even the negative result of one day's examination may be reversed by
the appearance of a contagious sore on the next. Women can transmit
syphilis passively by the presence of infected secretions in the genital
canal even when they themselves are not in a contagious state. In the
same way a woman may find herself infected by a man without any idea
that he was in an infectious state. She may in turn develop active
syphilis without ever realizing the fact. Medical examination of
prostitutes as ordinarily carried out does actual harm by deluding both
the women and their partners into a false sense of security. The life
which such women lead, with the combination of local irritation,
disease, and fast living, makes them especially likely to develop the
contagious mucous patches, warts, and other recurrences, and to relapse
so often that there can be little assurance that they are not contagious
all the time.

Under such circumstances one might almost expect every contact with a
prostitute on the part of a non-syphilitic individual to result in a new
infection. The factors which interfere to prevent such wholesale
disaster are the same which govern infectiousness throughout the
disease. Local conditions may be unfavorable, even though the germs are
present, or there may be no break in the skin for the germs to enter. If
the syphilitic individual is beyond the infectious period, there may be
no dangerous lesions. Here, as all through the history of infections
with syphilis, there is an element of the unexpected, a favoring
combination of circumstances. Sometimes when infection is most to be
expected it is escaped, and conversely it seems at times that in the
"sure thing," the "safe chance," and the place where infection seems
m