r. While
he has reason for gratitude that the former manual, referred to above,
has met with so favorable a reception, he can not but hope that the
present work will be found even more acceptable and valuable to both
practitioners and their patients.

It is but justice to say that the most essential principles of
_practice_ here presented did not originate with the present author, but
with PROF. C. H. BOLLES, of Philadelphia, their discoverer, from whom
the writer received his first introduction to them. Yet, the
_explanations_ here given of the Law of Polarization, as respects the
electric current in the circuit of the artificial machine, as well as
respecting the natural magnets and magnetic currents of the human
organism; the introduction of the _long cord_, with the explanation of
its advantages; and also nearly everything of the _philosophic theories_
here brought to view, the author alone is responsible for.

This work, like its little predecessor from the same pen, has been
adapted exclusively to the use of DR. JEROME KIDDER'S Electro-Magnetic
Machine, manufactured and sold, at present, at No. 544 Broadway, New
York; because the author, having used in his own practice a considerable
variety of the most popular machines intended for therapeutic purposes,
and having examined several others, believes this to be incomparably
_the best in use_. Dr. Kidder has, with most laudable zeal, pressed on
his researches and improvements in the manufacture of these instruments,
until there seems to be scarcely anything more in them to be desired.
They are certainly not equalled by any others in America, and probably
not surpassed, if equalled, by any in the world.

D. C.
PLAINFIELD, ILL., June, 1869.

CONTENTS.

Page.
INTRODUCTION xi

FIRST PRINCIPLES.

DR. JEROME KIDDER'S ELECTRO-MAGNETIC MACHINE 21
POLARIZATION 26
THE ELECTRIC CIRCUIT 28
POLARIZATION OF THE CIRCUIT 29
THE CENTRAL POINT OF THE CIRCUIT 33
THE CURRENT 35
MODIFICATIONS OF ELECTRICITY 36
THE VITAL FORCES--ANIMAL AND VEGETABLE 37
EXTENT OF ELECTRIC AGENCY 42