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.
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.
Fig. 13. Cylindrical Sponge-holder.
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.|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.
