Dr. Buchanan,[D] in his “Original Sketch,” gives us the history and some details of his discovery, based upon certain investigations of the nervous system. Already he was well versed in the phenomena of hypnotism, which is at this late day becoming a fashionable study and recreation of medical men. He had demonstrated the responsive action of cerebral organs to mesmeric touch and influence, and he was already acquainted with the curious psychological phenomena of sense and thought transference, of double consciousness, and all the nervous and pathological phases peculiar to natural and artificial somnambulism. His investigation for years of the nervous system had clearly shown him that its capacities were far more extensive, varied, and interesting than physiologists and philosophers either knew or were prepared to admit. He found in the nervous system a vast aggregate of powers which constitute the vitality of man, existing in intimate connection with the vast and wonderful powers of his mind. Was it possible or rational to suppose that this nerve-matter, so intimately co-related with mind, and upon which the mind depends for the manifestation of its powers, could be entirely limited to the narrow materialistic sphere assigned by physiologists? He thought not. In a conversation with Bishop Polk (who afterwards became the celebrated General Polk of Confederate fame), Dr. Buchanan ascertained that Bishop Polk’s nervous sensibility was so acute that, if by accident he touched a piece of brass in the night, when he could not see what he had touched, he immediately felt the influence through his system, and recognised an offensive metallic taste.