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THERAPEUTICS OF ELECTRICITY. 37 ;
When electricity is applied to the body, sponges of different
sizes, or polished metallic surfaces, known as " electrodes," the
metallic being the best, are employed, the effect upon the skin
being similar to what is caused by puncturing with many small
needles. The theory of electro-therapeutics is dependent upon the
following effects :
" If a portion of a motor nerve is included between the poles
of a galvanic battery, it is said to be polari%ed^ and in a state of
electrotonus. At the positive pole, the irritability of the nerve
is diminished, while at the negative it is excited and more sus-
ceptible to stimulation. The condition at the positive pole is
called anelectrotonus^ and that at the negative catelectrotonus. The
positive pole is known as the anode ; the negative, the cathode^ and
these give the name to the states described. A nerve is said to
be tetanized when the muscle supplied is thrown into a state of
permanent tetanic contraction by a rapidly intermittent current.
The passage of a number of these shocks for some time will
diminish the irritability of the nerve to such an extent that,
finally, there will be no further response. As an ascending cur-
rent causes a greater irritability in a nerve than a descending one
a descending one depresses excitability. The stimulus is felt at
the negative pole when the current commences, and when it is
broken it is felt at the positive pole. A shock is felt at the
opening of the weak currents ; with moderately strong ones it is
felt both at the opening and the closure. With very strong
currents, it is impossible to tell the points of sensation, as the
power of the nerve Is Impaired." The action upon involuntary
muscles is less than upon the voluntary, and, as regards the latter,
is the same, or nearly so, as long as the integrity of their im-
it
mediate nerve supply is concerned.
Degenerations and atrophies of muscles interfere to a consid-
erable extent with their susceptibility to electric currents ; hence,
it is better. In diseased conditions, to pass the current through the
nerve trunk which supplies them. The faradic current
has but a local effect, the deeper muscles and nerves
escaping.
When a metallic or sponge electrode is applied to the mois-
THERAPEUTICS OF ELECTRICITY. 37 ;
When electricity is applied to the body, sponges of different
sizes, or polished metallic surfaces, known as " electrodes," the
metallic being the best, are employed, the effect upon the skin
being similar to what is caused by puncturing with many small
needles. The theory of electro-therapeutics is dependent upon the
following effects :
" If a portion of a motor nerve is included between the poles
of a galvanic battery, it is said to be polari%ed^ and in a state of
electrotonus. At the positive pole, the irritability of the nerve
is diminished, while at the negative it is excited and more sus-
ceptible to stimulation. The condition at the positive pole is
called anelectrotonus^ and that at the negative catelectrotonus. The
positive pole is known as the anode ; the negative, the cathode^ and
these give the name to the states described. A nerve is said to
be tetanized when the muscle supplied is thrown into a state of
permanent tetanic contraction by a rapidly intermittent current.
The passage of a number of these shocks for some time will
diminish the irritability of the nerve to such an extent that,
finally, there will be no further response. As an ascending cur-
rent causes a greater irritability in a nerve than a descending one
a descending one depresses excitability. The stimulus is felt at
the negative pole when the current commences, and when it is
broken it is felt at the positive pole. A shock is felt at the
opening of the weak currents ; with moderately strong ones it is
felt both at the opening and the closure. With very strong
currents, it is impossible to tell the points of sensation, as the
power of the nerve Is Impaired." The action upon involuntary
muscles is less than upon the voluntary, and, as regards the latter,
is the same, or nearly so, as long as the integrity of their im-
it
mediate nerve supply is concerned.
Degenerations and atrophies of muscles interfere to a consid-
erable extent with their susceptibility to electric currents ; hence,
it is better. In diseased conditions, to pass the current through the
nerve trunk which supplies them. The faradic current
has but a local effect, the deeper muscles and nerves
escaping.
When a metallic or sponge electrode is applied to the mois-
