Electro-physiology and electro-therapeutics : showing the best methods for the medical uses of electricity / By Alfred C. Garratt.
135/740
- 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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You can copy, modify, distribute and perform the work, even for commercial purposes, without asking permission.
The image contains the following text:
The galvanic loop, point, and other shaped cautcrizers for
surgeons' and for dentists' purposes, can be had of the medical
electrical instrument maker, Mr. Thomas Hall, 13 Bromfield
Street.
Galvanometer.
For all the nicer tests in the study of electro-physiological
phenomena we are depending upon the Galvanometer-multiplier
and the Galvanoscopic frog. The former is delicately constructed
by our electrical and philosophi-
cal instrument makers. But the
latter requires precautions that
are to be remembered in pre-
paring it afresh from time to
time, as it must be done. First,
Fig. 13. Galvanoscopic Frog. tllO fl'Og HlllSt be fresll Cailgllt
and vigorous. The leg must be of very recent amputation.
Care must be taken to preserve and separate the ischiatic nerve
as long, and with as little handling, as possible. The leg must
then be perfectly insulated. We must close the circuit of the
experiment with the nerve alone, carefully avoiding any touch
of the muscles, so as to not include any of its influence. The
pendulous nerve, fresh and moist, must alone be touched in
two places by the two points that are suspected to be the poles
of the electromotor element that we desire to study. If all is
thus correctly done, the leg is then seen to contract instantly,
if any such force is found. Also, with a very great degree of
certainty, we may determine the direction of the current. For
this end we choose a frog's leg that is become enfeebled a lit-
tle, and thus some less excitable. If, now, the current is
brought to bear upon its nerve, in a direction up-running, i. e.,
from the leg towards the cut end of the nerve, we sec the con-
traction at the instant the current is closed. On opening the
circuit it is motionless. But if the current is directed so as to
course the nerve of the prepared leg in a reversed or down-
running direction, then the reverse obtains — i. e., motionless
on closure, but contraction on opening.