An examination of all crystal visions, so far as they are translated memories of actual experiences, will show this same evidence for a conserved residuum. That _conservation is not merely a figure of speech_ to express the ability to determine the recurrence of a previous experience, but means a specific residuum capable of independent and elaborate functioning, is brought out more conspicuously in those visions which are elaborately fabricated symbolisms of an antecedent experience. In other words, the vision is not a literal recurrence of a previous phase of consciousness, in that the latter has been worked over, so to speak, so as to appear in consciousness in a reconstructed form. Though reconstructed it either still retains its original meaning or is worked out to a completion of its thoughts, or to a fulfilment of the emotional strivings pertaining to them (anxieties, wishes, etc.). These visions, perhaps, more frequently occur spontaneously, often at moments of crises in a person’s life, but also are observed under experimental conditions. Sometimes they answer the doubts, scruples and other problems which have troubled the subject, sometimes they express the imaginary fulfilment of intense longings or of anxieties and dreads which have been entertained, or disturbing thoughts which have pricked the conscience.[46] We are obliged to conclude, in the light of experimental observations of the same class, that such phenomena are determined by the specific residua of antecedent thoughts which must be conserved and function in a specific manner to appear in this metamorphosed form. =Similar residual processes underlying post-hypnotic phenomena.=—Conserved experiences which give rise to more complicated secondary elaboration may be observed in suggested post-hypnotic phenomena. Experiments of this kind may be varied in many ways. The phenomenon may be an hallucination similar to the one I have just described in hysterics, or a so-called subconscious calculation. You suggest in hypnosis to a suitable subject that he shall multiply certain numbers, or calculate the number of seconds intervening between certain hours—let us say between 10:43 and 5:13 o’clock—the answer to be given in writing on a certain day. The subject is then awakened immediately, before he has time to do the calculation while in hypnosis. Later, if the experiment is successful, at the time designated the subject will absent-mindedly or automatically write the figures giving the answer.