Page 40 - My FlipBook

DENTAL MEDICINE.
3S
tened skin, a pricking sensation follows, attended with redness
and tingling, and this impression on the cutaneous nerves and
muscles is known as electro-muscular sensibility. The galvanic
current occasions a sensation of warmth, like that produced by a
local stimulant, such as a mustard plaster, and when the faradic
current is applied to the dry skin, or when the electrodes are but
lightly applied, there is produced a sensation of pain, and the pain
is the greater when caused by rapidly succeeding shocks than by
slow ones.
The galvanic current causes deeper impressions than the
faradic, and also electrolytic changes different from the faradic,
producing absorption and changing the structure of the different
tissues, and beneficial results have resulted from its application in
diseases of the brain. The physical effects of the galvanic cur-
rent upon the sympathetic nerve are dilatation followed by con-
traction of the pupil, diminished frequency of the pulse, and a
lowering of the tension of the carotid arteries. When electricity
is used for the purpose of diagnosis, the existence of local tender-
ness, exalted sensibility, anaesthesia, paralysis, diseases of the
brain, spinal cord, etc., may be ascertained. It has also been
used to determine the question of doubtful death, whether certain
affections are recent or of long standing, and to detect malinger-
ing. As various nervous diseases are associated with the loss of
such functions of muscles as contraction and sensation, or the
reverse, electricity determines the extent of such changes.
When employing the electric current, the anatomy of the part
affected should be well understood ; for example, for neuralgia of
the fifth pair of nerves one pole should be applied as near as pos-
sible to the point of exit of the nerve from the cranium, and the
other pole to the remote parts of distribution.
Galvanism and faradism are employed for the relief of pain
and spasm to improve the nutritive processes, and to restore de-
ficient muscular power, to stimulate sensation in nerves, to stim-
ulate secretion, to influence circulation, to cause absorption of
fluids, to bring about the absorption of morbid growths and de-
posits, to induce sleep, and in surgery, in the form of the galvanic
cautery. The galvanic current is considered to be the most