Electro-physiology and electro-therapeutics : showing the best methods for the medical uses of electricity / By Alfred C. Garratt.
149/740
- Publication/creation
- Boston : Ticknor and Fields, 1861.
- Physical description
- 3 unnumbered pages, 716 pages, 2 leaves of plates : illustrations ; 26 cm
- Contributors
-
Garratt, Alfred C. (Alfred Charles), 1813?-1891
Harvey Cushing/John Hay Whitney Medical Library
- Notes
-
3d ed. has title: Medical electricity
Includes index and testimonials
- Type/technique
- Electronic books
- Subjects
-
Electrophysiology
Electrotherapeutics
- Attribution and usage
-
This material has been provided by the Harvey Cushing/John Hay Whitney Medical Library at Yale University, through the Medical Heritage Library. The original may be consulted at the Harvey Cushing/John Hay Whitney Medical Library at Yale University.
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We find, also, the law that the characteristic properties of mag-
netic bodies are, volume for volume, those that contain the great-
est number of chemical atoms; while dia-magnetic bodies are
those that contain the least. Yet dia-magnetism is not a mag-
netism simply relatively more feeble. Both these classes of bod-
ies are influenced only so long as there is a body which deter-
mines the manifestation ; and that in proportion to the square
of the intensity of the magnet or of the current, and not to the
simple fact of intensity. This shows that these bodies are not
passive, but enter somewhat into the production of the given
result.
Induction Currents.
For a long time philosophers were impressed with the analogy
there seemed to exist between electric and magnetic phenomena.
There were manifested two magnetisms — the north and the
south poles ; as there were two electricities, plus and minus,
or positive and negative. Indeed, very many of the phenomena
of electricity in motion, are closely related to magnetism. The
attractions and repulsions manifested between the two magnet-
isms, as between the two electricities, are according to similar
laws.
In 1819 Professor Oersted, a Danish philosopher of Copen-
hagen, made the first scientific demonstration of the action of
electricity upon a magnet. As Dr. Benjamin Franklin had
demonstrated the identity of the lightning of the clouds with
the spark of the friction machine, — which, indeed, had long
been suspected and as much doubted, — so here was actually
proved that which had been so long suspected and sought for by
some, (while doubted and scouted by others,) but not where,
and in the way, it had been thought to exist. The finding of
M. Oersted was, that electricity acts upon a magnet, and that a
magnet, in its turn, acts upon electricity ; but only when the
electricity is in motion.
The following is his fundamental experiment: When the
poles of a galvanic battery are closed, so as to make a continu-
ous conductor, and if this wire, while the current is traversing