The so-called cases of double consciousness are perfectly simple in their explanation when the true nature of memory is borne in mind. In these cases the subject seems to lead a double life. The attacks usually come on suddenly. In the first attack all memory of the past is lost. The person is as an untaught child, and is forced to begin re-education. In some of these cases this second education has gone on for weeks, and advanced perhaps beyond the stage of reading, when suddenly the patient passes back to his original condition, losing now all memory of events which had occurred and all the knowledge acquired in what may be called his second state, but regaining all that he had originally possessed. Weeks or months afterward the second state reoccurs, the individual now forgetting all memory of the first or natural condition. It is usually found that events happening and knowledge acquired during the first attack of what we have called the second state are remembered in subsequent returns, so that the second education can be taken up at the point at which it was lost, and progress be made. This alternation of conditions has in some instances gone on for years, the patient living, as it were, two lives at broken intervals. This condition, usually called double consciousness, is not double consciousness at all, but, if the term may be allowed, double memory. It is evidently allied in its nature to the loss of the sense of personal identity. Certain phenomena of remembrance seen frequently in exhausting diseases, and especially in old age, show the permanence of impressions made upon the higher nerve-centres, and are also very similar in their nature to this so-called double consciousness. Not long since a very aged lady of Philadelphia, who was at the point of death, began to talk in an unknown tongue, soon losing entirely her power of expressing herself in English. No one could for a time make out the language she was speaking, but it was finally found to be Portuguese; and in tracing the history of the octogenarian it was discovered that until four or five years of age she had been brought up in Rio Janeiro, where Portuguese is spoken. There is little difference between the nature of such a case and that of the so-called double consciousness, both involving the forgetting of that which has been known for years.