ttery with the helix, the helical wires, and their appendages for
the vibrating action. But when a patient is under treatment, the
conducting-cords, the electrodes, and so much of the patient's person as
is traversed by the current while passing from the positive electrode
through to the negative electrode, are also included in the whole
circuit. And whatever elements may serve to conduct the current in any
part of its circuit--be they metal, fluid, nerve, muscle, or bone--the
same are all, for the time, component parts of _one complete magnet_,
which, in all its parts, is subject to the law of polarization,
precisely as if it were one magnetized bar of steel. Usually, however,
it is sufficient for _practical_ purposes to contemplate the circuit as
consisting only of that which the current passes through in going from
the point where it leaves the positive post and enters into the negative
cord, around to the point where it leaves the positive cord and enters
into the negative post.

POLARIZATION OF THE CIRCUIT.

I have said, in effect, a little above, that, while the current is
running, _the entire circuit is one complete magnet_, which extends
from the inner or positive sides of the zinc plates, where the current
commences, all the way around to the outer or negative aides of the zinc
plates, to which it returns. Viewed in this light its negative pole or
end is the battery fluid, next to the positive surfaces of the zinc
plates, and its positive pole or end is the brass clamp which, holding
the metals together, is in contact with the outer and negative surfaces
of the zincs.

But, for practical purposes, it is sufficiently exact to consider the
_magnetic circuit_ as extending only from the positive _post_ around
through the conducting cords, the electrodes and the person of the
patient to the _negative_ post. The negative end or pole of this magnet
is the wire end of the cord placed in the positive post, and the
positive end or pole is the wire end of the cord placed in the negative
post.

But any magnet may be viewed either as one whole, or be conceived as
composed of a succession of shorter magnets placed end to end. If we
view it as one entire magnet, we call the end in which the magnetic
essence is in greatest quantity the _positive_ end, and the end where it
is in least quantity the _negative_ end. But if we imagine the one
whole magnet as being divided up into several sections, then we conceive
of each se