Accurate interpretation of Poe's three tales of “mesmerism” depends on the correct historical definition of that term. It referred not to “hypnotism,” a later concept, but to “animal magnetism.” Hypnotism is a psychological phenomenon, a function of suggestibility, demonstrating the influence of one human will upon another. “Animal magnetism” was thought to be a physical “fluid”—comparable to electricity and other “imponderables”— pervading animate and inanimate Being, and acting as the unifier, the cohesive force which organizes both matter and mind. In “The Facts in the Case of M. Valdemar” it is this magnetic “current” which preserves Valdemar's body until the circuit between him and the magnetist is broken, and the body decomposes. In “A Tale of the Ragged Mountains” the fluid preserves Bedloe's body and his “nervous field” of identity; it also expands his consciousness into the past, which he relives as the magnetist writes his memoir. In “Mesmeric Revelation” Vankirk's consciousness is magnetized just on the verge of death; i.e., of absorption into the unparticled matter of a magnetized universe. His revelation of this universe relates animal magnetism not only to the attractionrepulsion force of Eureka, but to imagination and “ratiocination,” and the inevitable tension or “magnetism” between opposites in life. The unifying effect of animal magnetism, then, constitutes the “unity of effect” in these tales.