In treating of electricity as a remedial agent, I shall take it for granted that the reader is already acquainted with its chemical and physical properties, and with the prevalent opinions of its nature. In this place it is to be considered only in relation to its physiological and therapeutical effects, and to the methods of employing it as a remedy. As these effects are materially modified by the modes in which it is developed or excited, and applied, the latter division of the subject must be first treated of, in order that what may be said on the former may be understood.

I wish here to express my indebtedness for much which follows to the excellent work of M. Duchenne de Boulogne, who, by his thorough and laborious experimental investigation of electricity in its medical relations, the sagacity with which he has traced the various ramifications of its influence, and the ingenuity and perseverance with which he has applied the knowledge thus obtained to successful therapeutic results, has given a precision to the subject which it before much wanted, and has opened a new era in the history of the remedy.