s of syphilis and that it has quite
well-understood limitations. It has revealed an immense amount of
hidden syphilis, and in its proper field has had a value past all
counting. Experience has shown, however, that it should be checked up by
a medical examination to give it its greatest value. Just as all
syphilis does not show a positive blood test, so a single negative test
is not sufficient to establish the absence of syphilis without a medical
examination. In a syphilitic, least of all, is a single negative
Wassermann test proof that his syphilis has left him. In spite of these
rather important exceptions, the Wassermann test, skilfully done and
well interpreted, is one of the most valuable of modern medical
discoveries.

+The Blood Test in the Treatment and Cure of Syphilis.+--In addition to
its value in recognizing the disease, the Wassermann test has a second
field of usefulness in determining when a person is cured of syphilis,
and is an excellent guide to the effect of treatment. Good treatment
early in a case of syphilis usually makes the Wassermann test negative
in a comparatively short time, and even a little treatment will do it in
some cases. But will it stay negative if treatment is then stopped? In
the high percentage of cases it will not. It will become positive again
after a variable interval, showing that the disease has been suppressed
but not destroyed. For that reason, if we wish to be sure of cure, we
must continue treatment until the blood test has become negative and
stays negative. This usually means repeated tests, over a period of
several years, in connection with such a course of treatment as will be
described later. During a large part of this time the blood test will
be the only means of finding out how the disease is being affected by
the treatment. To all outward appearance the patient will be well. He
may even have been negative in repeated tests, and yet we know by
experience that if treatment is stopped too soon, he will become
positive again. There is no set rule for the number of negative tests
necessary to indicate a cure. The whole thing is a matter of judgment on
the part of an experienced physician, and to that judgment the patient
should commit himself unhesitatingly. If a patient could once have
displayed before him in visible form the immense amount of knowledge,
experience, and labor which has gone into the devising and goes into the
performing of this test, he would be more