All the varieties of supernatural conditions--conscious lucidity, conscious clairvoyance, sympathetic clairvoyance, sympathetic retrovision, direct clairvoyance, mental traveling, introvision and prevision, spontaneous retrovision--were formulated and added their quota to the general mystery. The doctrine of cross-magnetism, or the disturbing influence of different magnetizers, was developed, and became a favorite mode of accounting for failures of all kinds. Extravagant doctrines originating in other fields of pseudo-science were incorporated into magnetism; the magic mirror or crystal was one of these. The notion is doubtless very ancient,--compare the shew-stone of Dr. Dee (1527-1608),--and was revived by Baron Du Potet, who drew a black magic circle on the floor with a piece of charcoal; this the subject approached, stared at it fixedly, and seemed fascinated by it; grew excited, breathed hard, moved to and fro, and then saw visions in the magic mirror. "It was no dream nor nightmare; the apparitions were actually present. A series of events were unrolled before him, represented by signs and figures which he could understand and gloat over, sometimes joyful, sometimes gloomy, just as these representations of the future passed before his eyes! Very soon he was overcome by delirium, he wished to seize the image, and darted a ferocious glance towards it; he finally started forward to trample on the charcoal circle, the dust from it arose, and the operator approached to put an end to a drama so full of emotion and terror." "Darlingism" was a term brought forward by one Darling, who used a disc, said to be made of zinc and copper, to put his subjects to sleep. Like electro-biology, it was merely a new name for the same phenomena exhibited in connection with absurd theoretical notions. The phrenological manifestations, so unfortunately countenanced by Braid, continued to be exhibited by others in connection with the hypnotic state. Clairvoyance continued to be regarded as one of the most essential tests of the mesmeric condition, and took a prominent part in public exhibitions. Somewhat later it was incorporated into the equipment of spiritualism, and this movement probably exerted a mystic influence upon mesmerism.