reputation have advocated the habitual use of the galvanometer, not
alone by medical men trained to precision of observation, but by
private patients as “_enabling them to carry on the treatment at home
with all the accuracy desirable!_” The prospect of the ordinary patient
provided with a battery, the use of which he is complicating by a
galvanometer, is anything but reassuring to those physicians who not
only prescribe electricity, but are themselves habituated in applying
it--which, by the way, is a very different thing--and who have had
frequent experience of the manner in which patients misunderstand,
or fail in correctly carrying out, the most explicit directions.
Electricity will be left in the hands of specialists, and necessarily
do but a tithe of the good it is capable of affecting, until the
mass of the profession can be induced to master the few preliminary
details essential to its successful application, and I fear that the
suggestions that have been made--suggestions which I believe to be
entirely without foundation--that there exist practical difficulties to
its dosage, will tend to postpone rather than to accelerate its more
extended use.
Should any of you desire to use a galvanometer, that patented by
Sprague, of Birmingham, is the one most adapted for use in medicine.
Electricity is a force, and as with other forces it has its standard
of measurement. In mechanics we know that the power sufficient to
raise one pound to the height of one foot is the basis of measurement.
Similarly in electricity the unit of measurement is the force which
will raise one gramme to the height of one metre, and the standard
multiple of this was called a “British Association Unit,” or shortly, a
“B.A.” unit, and it is now called an “_Ohm_” when used to measure the
resistance offered to the current, and a “_Veber_” when used to measure
the strength of the current itself. The ordinary galvanometer is
founded on the principle that a magnetic compass needle has a tendency
to place itself at right angles to a current of electricity, and the
degree to which the needle is deflected is a measure of the quantity
of electricity, but the angle of deflection is not proportionate to
the current strength, and it differs in different galvanometers; but
in “Sprague’s Galvanometer” the dial is divided, not into degrees,
but into divisions of thousandths of _Vebers_--divisions which were
obtained by noting the deflections given by the needle with currents
of known strength. I am indebted to Mr. Sprague for his courtesy in
endeavouring to so modify his galvanometer as to render it available as
a graduator of doses of interrupted Voltaic electricity, but although
he has not succeeded in doing this, he has constructed for me an
instrument which, supposing that a battery be partially exhausted,
will indicate with precision the absolute strength of, say, twelve
of its cells as compared with twelve newly-charged cells, and also
the condition of each individual cell, points often of much practical
convenience in an Hospital Electrical Room.
[9] A little care is needed to regulate the vibrating needle. The
spring should but _barely touch_ the hammer, the adjustment being
almost entirely regulated by the protrusion or retraction of the needle
by the action of its screw; and the _slightest twist_ of this screw
will be sufficient. When the vibration is uneven or stops, and careful
manipulation of the needle fails to re-establish it, remove the needle
and clean its point as directed in the text.
LECTURE II. METHODS OF APPLYING ELECTRICITY.
GENTLEMEN,
[SN: Résumé of First Lecture.]
In our first Lecture we studied the different kinds of electricity
employed in medicine, and the construction and management of batteries.
I reminded you that we made use of three kinds of electricity;
firstly, of friction or static electricity, _Franklinism_; secondly,
of the electricity of chemical action, _Voltaism_, or _Galvanism_;
and, thirdly, of induced electricity, _Faradism_:--that there had
been certain difficulties in the employment of Franklinism, but
that these difficulties no longer existed; that Voltaic electricity
was electricity in motion, or current electricity, but that
while its current (unless artificially interrupted) was always
_continuous_--flowing, that is, in an unbroken stream--and from the
positive to the negative pole, until the battery was exhausted--it by
no means followed that it was _constant_, that is, that it did not vary
appreciably in power during application; that only batteries supplying
a fairly constant current were fitted for medical use, and that all
others should be rejected. We then considered different batteries,
both fixed and portable; that while large fixed low tension batteries
were unquestionably superior in their therapeutic effects, patients
unfortunately were not always movable, and that a portable battery
became, therefore, a _sine quâ non_; that portable batteries might
be conveniently divided into two classes, one in which electricity
was generated by the elements being immersed in an exciting fluid
only during actual use, and being taken out of the fluid immediately
after use; and the second that in which no removal of the elements was
necessary; that the Voltaic current was graduated into doses by some
arrangement determining the number of cells to be employed in each
case, but that this method, while practically useful and sufficient,
failed to convey an exact idea of a measured and unvarying quantity
of electricity; and that it had been contended that by the use of a
galvanometer, doses of electricity might be as accurately administered
as so many grains or minims of ordinary medicines, but that, perfect
as the theory might be, I had personally failed to obtain help in
practice from a galvanometer; that next in importance to a method of
dosage, was it to be able to instantly change the direction of the
current, or to at once turn it “off” or “on,” in addition, of course,
to the fundamental requisite of a continuous supply of electricity of
sufficient quality and quantity.
We next considered the induced or _Faradaic_ current, so-called,
which I reminded you is not a current at all, but a rapid discharge
or succession of those momentary shocks, each perfectly distinct in
itself, and separated by an appreciable interval of time from its
fellows, which Faraday discovered to be generated or induced by a
Voltaic current flowing along a wire in other wires parallel to, but
separated from, the first wire; that by winding the two wires upon two
movable reels and introducing one within the other, not only might
these _secondary_ currents be multiplied indefinitely in proportion to
the number of spirals of wire, but by introducing or withdrawing the
one from within the other an exact method of graduation was afforded
us. I pointed out to you that there was no therapeutic distinction
between the so-called primary and secondary currents, and I recommended
you therefore to use only the currents of the secondary coil. I then
showed you the construction of Faradaic instruments, and of instruments
combining both Voltaic and Faradaic currents, and our survey was
completed by a consideration of the different varieties of conducting
wires or cords, and my recommendation of thin gutta-percha covered
copper wire as generally superior to any other form. We have to-day
to study methods of applying electricity, and to learn how to use the
instruments, with the construction and properties, of which I trust you
are now familiar; and, Gentlemen, it is well worth your while to have
obtained this knowledge, for its possession will not only enable you to
readily rectify any faults in the working of your batteries, but the
necessity of sending them to the instrument-maker may be often avoided.
We have already studied methods of applying Franklinism.[10]
Voltaization and Faradization may both be applied either generally--as
in the different forms of electrical baths--or locally.
[SN: The Application of Electricity.]
A convenient method of applying electricity, when very strict
localization is not required, is to insert the feet and hands of the
patient, or one foot and one hand, as the case may be, in separate
vessels containing tepid salt and water with which the conducting wires
of the battery are in contact, the current being allowed to circulate
during the time required. Ordinary foot-pails, basins, or jugs, will
fulfil every requirement; while thick telegraph wire answers well to
connect the battery with the vessels of water, as it is little liable
to break and wears well. A variety of the constant current (originated
by Dr. Radcliffe) is very readily applied in the way just described,
with the addition only of some means of insulating the patient and the
accessories, and of a length of ordinary uninsulated copper wire.
[SN: Radcliffe’s Positive Charge.] Dr. Radcliffe believes that an
administration of _positive_ Voltaic electricity, somewhat analogous
to the charge of Franklinic electricity, is frequently beneficial. He
insulates the patient and the accessories, and having connected the
negative pole with the earth by a wire which he calls a “ground-wire,”
he allows the current to pass. With careful insulation the negative
electricity passes away by the wire, and while the current circulates
the patient continues “charged” with positive electricity. There must
be two wires from the negative pole, one to be applied, as well as
the positive, to the patient, and the other taken “to earth.” This
latter may be conveniently attached to a chandelier or gas-pipe,
which always gives a direct metallic conduction to the ground. A
perforated vulcanized indiarubber mat, or a sheet of gutta percha, or
a glass-legged stool can be employed to insulate the patient and the
accessories.
[SN: The Electric Bath.]
There is another generalized application which has been much advocated,
and remarkable statements have been put forth, not only of its curative
power in almost every disease, but also of its purely physical and
chemical effects--I refer to that by “Electric Baths,” several
establishments of which exist in London, but you need not send your
patients to them. You can teach them how to take an electric bath in
their own bed or bath-room. A bath sufficiently large for the patient
to recline in it should be insulated by glass supports (four stout
tumblers will do very well), and filled with water at a temperature of
95 to 100 degrees. A metallic plate in connection with one pole may be
inserted at the head, and a second plate in connection with the other
pole at the foot of the bath. The patient should be protected from
direct contact with either plate by sitting upon a wooden framework.
With a sufficiently powerful current, a portion of the electricity
will pass through the body of the patient reclining thus between the
poles. Another method is to connect the water with one pole, and for
the patient to grasp in his unimmersed hands a copper bar covered with
wet flannel, and in connection with the second pole of the battery; or
a conductor from this second pole may be held almost, but not quite,
in contact with any part of the body immersed in the water. Either
the Voltaic or Faradaic current may be used. Ordinary water with the
Faradaic current, but salt and water, or acidulated water, with the
Voltaic.
[SN: General Faradization.]
Another more generalized application is that introduced by Beard and
Rockwell, under the name of “General Faradization.” The patient sits
with his naked feet upon a sheet of copper connected with one pole,
while the other pole is connected by a moistened sponge with the
left hand of the operator, who passes his disengaged hand, slightly
moistened, over the muscles of the patient, and sometimes over his
whole body. The current, I need hardly say, passes through the body of
the operator before it reaches the patient, and the sensation he feels
is his chief guide to its graduation.
[SN: Centralized Galvanization.]
Another general application is the “Centralized Galvanization” of the
same authors, in which their object is to bring the whole central
nervous system under the influence of the Voltaic current.
They place one pole--usually the negative--at the epigastrium and pass
a large moistened sponge from the positive pole over the forehead and
top of the head, along the inner border of the sterno-mastoid, from the
stylo-mastoid fossa to the sternum, and down the entire length of the
spine, from the nape of the neck to the sacrum. The brain, sympathetic
and spinal cord, and the pneumogastric nerves are thus submitted to the
influence of the current.
[SN: Localized Electrization.]
But the great majority of cases require--not a generalized, but a
strictly localized application, and for the fundamental principles of
all methods of localized electrization we are indebted to the late Dr.
Duchenne (the “father of electro-therapeutics”), for before him no one
had attempted any local application of electricity that could properly
be so called. Indeed, to Duchenne may be fairly ascribed the very
birth of medical electricity as a branch of therapeutics, and in the
true and kindly words of the _Lancet_, when announcing his death:--“No
field of work was ever seized upon with more eagerness; ever cultivated
with more earnestness; or perhaps ever made to yield a better harvest
than that which the discovery of induced electricity placed at the
disposal of the man whose genius was the first to recognize, and
his talents to secure, the opportunity it afforded. Taking his work
at its lowest estimate, he was a man to whom medical science owes a
large debt of gratitude, and whose memory deserves a warm tribute of
regard.” Duchenne’s two test experiments, demonstrating the fundamental
principles of his method, I will now repeat upon the posterior surface
of my left forearm. I propose to arrest Faradism in the skin, without
allowing it to stimulate the subjacent muscles. To do this it is
necessary for the skin to be quite dry--moisture, as you know, being
a conductor of electricity--and to make sure of sufficient dryness, I
sprinkle the skin with a little starch powder. I now apply to the dry
skin the dry metallic conductors of an induction instrument in action.
I am afraid you cannot see, Gentlemen, the small sparks produced as
the two electricities combine upon the cutaneous surface, or hear
the slight crackling sound produced, but you observe no muscular
contraction, and what I feel is a superficial and evidently cutaneous
sensation. I now replace the dry conductors by well-moistened sponges.
You observe that I have not altered the power of the current, but that
there is energetic contraction of the extensor muscles. This is quite
involuntary, and is due to the electric irritation of the branches of
the motor nerves.
It follows from these experiments that we may, at pleasure, arrest
electricity in the skin, and that without puncture or incision we may
make the current traverse the skin, and concentrate its action upon
subcutaneous organs. It was at one time objected that the muscular
contraction was the result--not of irritation limited to the muscle or
its motor nerves--but of reflex action; but Duchenne demolished this
objection by a vivisection. Having removed the skin from the face of a
living rabbit--to whom chloroform had been administered--he divided the
facial nerve of one side only, in order that the muscles supplied by
it might be cut off from all connection with the cord. He then applied
electric excitation to each muscle of the face, alternately, on the two
sides. The muscles contracted separately and equally on both sides.
He then destroyed the brain of the same animal, in order to place the
cord in a condition favourable to the production of reflex action, and
again excited the muscles as before. The results were absolutely the
same.[11]
Muscular electrization may be produced either--as I have just shown
you--by placing the conductors upon the muscle itself, a procedure
termed _direct_ or _intra-muscular_ electrization, or by exciting only
the motor nerve trunk, which is termed _indirect_, or _extra-muscular_
electrization, and which we shall consider presently.
[Illustration: FIG. 13. Cylindrical Sponge-holder.]
[SN: Different kinds of Rheophores.]
For direct excitation of the larger muscles it is convenient to use
well-moistened sponges, contained in cylinders of different sizes,
or metallic disks, covered with wet leather and having conveniently
shaped handles. A useful size of cylinder is one such as this (see
Fig. 13), having a depth of about 1-1/2 by 1-1/8 inches, which allows
the sponge to fairly fill it, while in such forms as this--6 inches
by 1--when the sponge is inserted the lower three-fourths of the
cylinder is empty, and the conduction of the current liable to become
imperfect. Such a cylinder as this, without any insulating handle at
all, is worse than useless, and is a still persisting relic of the
barbarous time when the patient was invariably electrized by causing
him to hold the conductors one in each hand, a proceeding extremely
dangerous in certain pathological conditions, and in other cases not
likely to be of benefit to him. The insulating handles should be well
hollowed out, that they may be used, lying comfortably between the
fingers, when holding two in the same hand. The disk rheophore (see
Fig. 14), a metallic button covered with wash-leather, is extremely
useful; it has the advantage over the sponge of allowing firm pressure
to be made without the inconvenience of water being squeezed out, while
by using its edge it may be made to answer in the majority of cases
for a pointed conductor, which is fitted chiefly for application to
very small muscles, such as the interossei and some of those of the
face. The wire is attached to the conductor by being screwed into the
socket (see a′, Fig. 14). A conducting cord is very apt to get frayed
at the point of juncture, and that the wire which I recommend is
not open to this objection is not the least of its advantages. [SN:
Direct Electrization.] In direct electrization the rheophores should
be firmly pressed down upon all points of the surface of the muscle,
that all of its fasciculi may be equally electrized. With the Faradaic
current it is convenient to apply the rheophores, held in the same
hand (see Fig. 15), for from twenty to thirty seconds, to every part
of the surface of the muscle, or group of muscles, promenading them
as nearly as may be in lines from the origin to the insertion of the
muscles. If the rheophores are not held in the same hand care should be
taken to keep them near to one another, for the tension or penetrating
power of Faradism is so great, that without this precaution there will
be liability to excite reflex action. With the interrupted Voltaic
current this liability does not exist, and a better plan when using it
is to hold the sponge from the positive pole stationary, near to the
origin of the muscles, and to stroke or paint as it were the entire
muscular surface with the sponge from the negative pole, gliding it in
lines from the position of the positive. In using the constant Voltaic
current both sponges must be held quite immovable, and so applied
it differs altogether in its effects from the very same strength of
current interrupted by moving the conductors. I will demonstrate
these different applications upon the extensors of my left wrist and
fingers--Faradism--Voltaism--Constant Current.
[Illustration: FIG. 14. Metallic Disk, covered with Wash-leather.]
[Illustration: FIG. 15. Method of holding Sponge-holders with Sponges
inserted.]
[SN: Indirect Electrization.]
Indirect, or extra-muscular electrization, next claims our attention.
You will recollect that it is produced by acting upon the special
nerve trunk and its branches, instead of by placing the rheophores
upon the muscle itself. We may thus call a motor nerve into action
without affecting the cutaneous nerves, and with a minimum of power
of current, and necessarily a minimum of sensation which hardly ever
need amount to actual pain. This method is preferable, therefore, in
cases where we desire to produce muscular contraction and as little
sensation as may be, and again when the sedative influence of the
constant Voltaic current is required to be localized in any special
nerve. In its application it is convenient to place a good-sized
sponge connected with one pole upon an indifferent part of the body,
such as the sternum, and to apply a pointed conductor from the
second pole directly over the course of the nerve it is desired to
act upon. Speaking generally, these motor points as they are called
may be selected by reference to a good anatomical plate, but only
approximately, for we know that it is common to find variations
in the course of the nerves and in the mode of their distribution
among the muscles, and this being so, it is well when we propose to
act upon a motor or mixed nerve (which is not paralyzed), to make
sure that we are localizing the current in it by producing for a
moment the contraction of its muscles and then marking the spot by
touching it with a pencil of nitrate of silver. This, of course, is
only necessary where in our subsequent electrization we do not wish
muscular contraction, as in the treatment of neuralgia.[12] I will
demonstrate indirect electrization by Faradizing the median nerve in my
left forearm above the wrist, and before it passes beneath the annular
ligament of the carpus. It lies a little below the surface, between
the tendons of the flexor carpi radialis and palmaris longus. You
observe that its muscles powerfully contract and oppose the thumb to
the other fingers, at the same time abducting it. There occurs also a
slight flexure of the first phalanges of the index and middle fingers.
Professor Ziemssen in his work on Medical Electricity has published
some extremely accurate plates of the motor points of the body, and I
have grouped together the more important of them in a chart or map for
convenient reference.[13] Ziemssen’s method of procedure was to find
out experimentally the points where the application of electricity most
readily produced muscular contraction. He then marked these points with
coloured chalk, and after a sufficient number of trials with nitrate of
silver. Photographs of the parts thus marked were taken and afterwards
transferred to the wood blocks. These figures may therefore claim to be
true to Nature, although they may not be absolutely correct for every
individual. Ziemssen verified their approximate exactitude by following
the course of the nerves very accurately in the dissecting-room and
observing their points of entrance into, and their course within, their
muscles, with constant reference to the surface of the body; but he
was not completely satisfied until he had determined the motor points
upon the skin immediately after death, and before the reaction to
electricity had disappeared, and submitted these points to the scalpel.
The results of the three methods coincided perfectly.
[SN: Cutaneous Electrization.]