WHILE OCCUPIED some few days ago in preparing an electromagnetic machine for application to a patient, an old servant (upwards of 80 years), who had long been subject to violent spasmodic tremblings of both arms, chanced to enter the room.

More, in the spirit of levity than either philanthropy or philosophy, I asked her to take hold of the electrodes of the machine, at the same time pressing the bundle of soft wires some distance into the centre of the helix, so as to give a pretty sharp shock.

Although much startled at first, she continued to hold the electrodes for a short time, perhaps a minute or upwards. She then left the room, but returned almost immediately, and with a half-terrified, half-triumphant air she declared that since she got the shock the trembling had almost completely vanished from her arms.  And in order to demonstrate  the truth of her statement, she held in her hand a rather heavy tray, with a tea-cup and saucer  placed upon it, with scarcely any perceptible motion. Had she attempted to do so before the application, the experiment, no doubt, would have proved in the last degree disastrous to both the tray and its contents. 

Now occurred the most interesting and instructive feature in the case. Having held the tray for some time in the right hand, which had previously been very much worse than the other, she took hold of it with her left – I suppose under the impression that, as the right had been so very much improved, the left, from not being previously so much affected, would be completely cured.  Her disappointment was, however, very great when she found that, so far from being perfectly restored, it was decidedly worse than before the application had been made. So much so, that she rather indignantly exclaimed, “Oh, sir, you only took it out of the right arm and sent it into the left.” Although at first rather perplexed by the phenomenon, an explanation  quickly presented itself, which was afterwards verified by events.

Upon examination I found she had held the negative electrode in the right hand, while the left grasped the positive. The effect of this proceeding was, of course to cause the current to pass up the left arm, across the chest, and down the right arm, producing in the case  of the down-running current a decidedly tonic and salutary effect, while the opposite result was caused by the up-running or inverse current.

That  such was  the correct explanation of the chance that was caused by the application, was fully and most satisfactorily proved to me by reversing the electrodes on the following day, placing the negative in the left hand and vice versa. The result of this manoeuvre was to restore the left arm to its former strength without producing much appreciable effect upon the right, thus plainly demonstrating the tonic effect of the direct current.

I now, however, adopted what appears to me to be the correct and scientific mode of application, by bathing the fore-arm and hand with the negative moist sponge electrode, while the positive electrode was directed to the vicinity of the shoulder-point and brachial plexus, thus applying a direct current to the affected muscles. The result of the treatment was the best proof of the correctness of the principle upon which it was founded. A few applications repeated every second day completely restored her, and now her greatest source of enjoyment is to display her powers as an equilibrist to anyone who may feel an interest in the matter.