It is seldom that so direct and forcible an application of experimental results to actual mental experiences occurring under familiar circumstances can be made, as is the case in regard to this noteworthy investigation of Messrs. Hodgson and Davey. This investigation, almost at one stroke, throws a blinding light upon the entire field of the phenomena; accounting in large part for the vast aggregate of testimony in favor of miracles by actual witnesses, demonstrating the readiness with which we may unwittingly deceive ourselves by false observation and others by lapses of memory, as to what we actually witnessed; and again presenting the nature of these fallible characteristics of sense-perception and memory, of inference and judgment, so strikingly and tangibly as to serve as a classic illustration for the psychologist. The practical import of these considerations has been quite generally disregarded by upholders of the spiritualistic hypothesis, and has by no means been fully appreciated by those who lay claim to an opinion upon the significance of spiritualistic manifestations, and who discuss the psychological questions which they involve. It is pertinent to add that after Mr. Davey's death, Mr. Hodgson felt free to publish a precise account of what Mr. Davey actually did during the slate-writing séances.[7] The description from before the footlights may thus be compared with the account from behind the scenes; and although verbal accounts must always be weak and lack the realistic touch of the _mise en scène_, yet this account makes possible a kinetoscopic reproduction, as it were, of the original sitting; we may observe the point at which the several sitters committed their faults of defective observation or report; we may examine at leisure the several steps in the performance which the eyes overlooked in the hasty single glimpse afforded by the sitting itself; we may attend to details which in the original sitting reached only the outlying and evanescent phases of consciousness. But, on the whole, the psychological comprehension of the "séance" was sufficiently manifest without this disclosure of the _modus operandi_; the disclosure has its value, however, in removing the possibility of certain forms of criticism of the results, in presenting data by which the specific nature of mal-observation may be more concretely studied, and in convincing the more obstinate and skeptical of how natural it is to err in matters beyond the range of one's intimate experience.