for the reason that many of the scientific class doubt the existence of any spirit beyond the earth-life, that many of the religious class question the possibility of freed spirits returning to earth, and that many of an intermediate class consider the manifestations too puerile and the mental communications given too unsatisfactory and too far below the mental calibre of the professed speakers to be worthy of assignment to any such source. These communications seem usually painted by the mind of the medium, and are often notably feeble, absurd, and valueless. To the members of this class the second explanation is the only tenable one,--namely, that there are certain extraordinary powers resident in the nervous organism which are capable of acting in opposition to the ordinary energies of nature; that an intangible material exists outside the body and penetrates physical objects, through whose aid the nerve-power somehow operates to produce sounds and motions of bodies; that this nerve-power may act unconsciously to the person who possesses it in even a highly-developed state; that its action may be controlled by the mind, acting either consciously or unconsciously; that old and long-forgotten stores of the memory may take part in this action; and that other minds may act through the medium's mind and set in action his psychic powers unconsciously to himself. That there is such a supersensible substance, and that the human mind has such hitherto unknown powers, is not easy to admit. And yet when we consider all the facts bearing upon the case it becomes equally hard to deny. The history of mankind is full of stories of occult operations and so-called supernatural performances. Those recorded are, of course, but the merest fraction of those that have been observed. At the present day this world of mystery seems everywhere around us. Outside of what is put on record, almost every person one meets can relate some such mysterious occurrence which has happened to himself or some of his acquaintances. That a very great proportion of this has been self-deception must be admitted. But all mankind is not blind and gullible; and if we strain these stories of the marvellous through the sieve of criticism, some considerable residuum will remain, which must be accounted for by another theory than that of delusion.