thods of Treating Disease.+--In trying to treat diseases
caused by germs, the physician finds himself confronted by several
different problems. Certain of these diseases run their course and the
patient gets well or dies, pretty much regardless of anything that can
be done for him. In certain others, because of our knowledge of the way
in which the body makes its fight against the germ, we are able either
to prepare it against attack, as in the case of protective vaccination,
or we are able to help it to come to its own defense after the disease
has developed. This can be done either by supplying it with antitoxin
from an outside source, or helping it to make its own antitoxin by
giving it dead germs to practise on. In the third group, the smallest of
the three, we are fortunate enough to know of some substance which will
kill the germ in the body without killing the patient. For such diseases
we are said to have a "specific" method of treatment. Syphilis is one of
these diseases. It is not to be understood that there is a sharp line of
division between these three groups, since in every disease we try as
far as possible to use all the methods we can bring to bear. In
pneumonia we have to let the body largely make its own fight, and simply
help it to clear out the poisons formed by the germ, and keep the heart
going until the crisis is past. In diphtheria, nowadays, we help the
body out promptly by supplying it with antitoxin from an outside source,
before it has time to make any for itself. We do the same thing for
lockjaw if we are early enough. We practise the body on dead typhoid
germs by vaccination until it is able to fight the living ones and
destroy them before they get a foothold. The diseases for which we have
specific methods of treatment are few in number, and each has associated
with it the name of a particular drug. Quinin kills the germ of malaria,
sodium salicylate cures inflammatory rheumatism, and mercury cures
syphilis. To mercury in the case of syphilis must now be added salvarsan
or arsenobenzol ("606"), the substance devised by Ehrlich in 1910, which
will be considered in the next chapter.

The action of a specific is, of course, not infallible, but the failures
are exceptional, so that one feels in attacking one of these diseases
with its specific remedy as a man called upon to resist a savage beast
would feel if he were armed with a powerful rifle instead of a stick.
The situation in syphilis, for