HYDROPHOBIA, OR RABIES. 309

lent material that would certainly kill an unprotected
animal.

It is remarkable that this thought, which was a theory
based upon a broad knowledge, but experience with
comparatively few bacteria, should every day find more
and more grounds for confirmation as our knowledge
of immunity, of toxins, and of antitoxins progresses.
What Pasteur did with rabies is what we now do in
producing the antitoxin of diphtheria—i. e. gradually
accommodate the animal to the poison until its body-cells
are able to neutralize or resist it. As the poison cannot
be secured outside of the body because the bacilli, micro-
cocci, or whatever they may be cannot be secured outside
of the body, he does what Behring originally did in diph-
theria—introduces attenuated poison-producers—bacilli
crippled by heat or drying, and capable of producing only
a little poison—accustoms the animal to these, and then to
stronger and stronger ones until immunity is established.

The genius of Pasteur did not cease with the produc-
tion of immunity, but, we rejoice to add, extended to the
kindred subject of therapy, and has now given us a c^lre
for hydrophobia.

For the production of a cure in infected cases very
much the same treatment is followed as has been de-
scribed for the production of immunity. The patient
must come under observation early. The treatment con-
sists of the subcutaneous injection of about 2 grams of
an emulsion of a rabbit's spinal cord which had been
dried for from seven to ten days. This beginning dose
is not increased in size, but each day the emulsion used
is from a cord which has not been dried so long, until,
when the twenty-fifth day of treatment is reached, the
patient receives 2 grams of emulsion of spinal cord dried
only three days, and is considered immune or cured.

It will be observed that this treatment is really no
more than the immunization of the individual during the
incubation stadium, and the generation of a vital force—
shall we call it an antitoxin ?—in the blood of the animal