One of the most remarkable forms of superstition, which still takes a very active part in modern life, is _spiritism_. It is a surprising and a lamentable fact that millions of educated people are still dominated by this dreary superstition; even distinguished scientists are entangled in it. A number of spiritualist journals spread the faith far and wide, and our "superior circles" do not scruple to hold _séances_ in which "spirits" appear, rapping, writing, giving messages from "the beyond," and so on. It is a frequent boast of spiritists that even eminent men of science defend their superstition. In Germany, A. Zöllner and Fechner are quoted as instances; in England, Wallace and Crookes. The regrettable circumstance that physicists and biologists of such distinction have been led astray by spiritism is accounted for, partly by their excess of imagination and defect of critical faculty, and partly by the powerful influence of dogmas which a religious education imprinted on the brain in early youth. Moreover, it was precisely through the famous _séances_ at Leipzig, in which the physicists, Zöllner, Fechner, and Wilhelm Weber, were imposed on by the clever American conjuror, Slade, that the fraud of the latter was afterwards fully exposed; he was discovered to be a common impostor. In other cases, too, where the alleged marvels of spiritism have been thoroughly investigated, they have been traced to a more or less clever deception; the mediums (generally of the weaker sex) have been found to be either smart swindlers or nervous persons of abnormal irritability. Their supposed gift of "telepathy" (or "action at a distance of thought without material medium") has no more existence than the "voices" or the "groans" of spirits, etc. The vivid pictures which Carl du Prel, of Munich, and other spiritists give of their phenomena must be regarded as the outcome of a lively imagination, together with a lack of critical power and of knowledge of physiology.