As it is one of our objects in our practice here to study the scope and the limits of electricity as a remedy in disease, it seemed to me not inappropriate to devote my first Lectures to electro-therapeutics; and the more so, as few medical men have a practical knowledge of the subject; and I fear that the profession generally, through lacking this practical knowledge, are to some extent responsible for the utter and astounding recklessness with which the laity--ever ready to rush in where physicians fear to tread--are prone to apply painful and dangerous electrization, not to themselves, but to their suffering friends; while it is still too common for the medical practitioner (as quoted by Golding Bird upwards of forty years ago) to consider that when his fiat has gone forth “let the patient be electrified,” he has done all that is necessary, while the patient usually carries out this mandate by the purchase of a rotary magneto-electric machine, and by using it according to the directions of its maker, who is generally about as well fitted to teach its application in disease as is the maker of an amputating knife to operate with it! The almost complete absence in the medical schools of the great hospitals of opportunities for an adequate study of electro-therapeutics, the importance of the subject, and the widespread attention that it is awakening throughout the profession, have also determined me to sketch as briefly as is consistent with clearness the present position of the science and practice of medical electricity, and especially of its practice.[3] Electricity, Gentlemen, is by no means one of those remedies that, failing to do good, is little likely to do harm. On the contrary, in injudicious hands, it is potent for evil, while the benefit to be derived from it is in exact proportion to the judgment and care with which it is administered. Moreover, the results of its employment are dependent, more than with any other therapeutic agency, upon the methods by which it is applied--methods that should be familiar, not alone to a few specialists, but to every practitioner. Addressing you who are engaged in active practice, with little time to devote to medical electricity, it will, I think, be more acceptable for me not to weary you with a tedious discourse upon the elementary principles of electricity, for the practical application of these matters concerns rather the instrument-maker than the medical practitioner, and I shall discuss none of them, except incidentally, and _with precise reference to their application to medicine_. Besides, we know little of them, and I cannot forget that Faraday said that “he once thought he knew something about electricity, but the more he investigated it the less he found he understood it.” Let us then be content with its definition as a “FORCE,” “pervading all nature, latent in every substance, and liable at any moment to be excited by mechanical or chemical means.”