This section is from the book "A Treatise On Therapeutics, And Pharmacology Or Materia Medica Vol1", by George B. Wood. Also available from Amazon: Part 1 and Part 2.
As electricity is probably identical under whatever aspect it may present itself, its effects under similar circumstances are probably also identical; but, in the different conditions in which it is actually developed, it exhibits striking differences of operation, which render necessary the consideration of it, in the present relation, as before in regard to the methods of development, under its several distinct forms. Its characteristic effects, as a general rule, are to excite sensation and muscular contraction, and, indeed, to augment the functions of all the organs on which it may be brought specially to act; consequently, under favouring circumstances, to promote digestion, absorption, circulation, animal temperature, secretion, and the nutritive and assimilative processes; in other words, it appears to be capable of acting as a universal stimulant, though more especially directed to the vital properties of sensibility and muscular contractility. In its influence upon sensation, it produces effects corresponding with the functions of the several senses; causing pain, when acting on the nerves of general sensation; the perception of light, when on the organ of vision; a peculiar taste, when on the tongue and palate; smell, when on the olfactory organs; and sound, when on the ears. Muscular contraction is caused by it, whether directed to the muscle exclusively, to the nerves of motion, or to the nervous centres of motion In the higher exertion of its powers, like some other stimulants, it has the effect of overwhelming the vital functions, and producing apparent direct prostration, even to a fatal issue. Witness the effects of a violent shock, and especially of a stroke of lightning, which often destroys life instantaneously, and, when it fails to do this, generally leaves the patient for a time more or less prostrate, senseless, and paralyzed.