[Footnote 69: It is a question of considerable psychological interest, as to how the ideas of birth and intra-uterine life come to acquire the significance which we have found them to possess. In what way for instance do we come to associate life within the womb with freedom from effort, difficulty or danger? In the majority of cases, not from conscious thinking on the subject; on the contrary, the connotation of safety and effortlessness would seem in some way to belong inherently to the idea of pre-natal existence from the very beginning, or at any rate to have become attached to it through a purely unconscious process of association. Again, how do we come into possession of the ideas of birth and pre-natal life themselves? Is the knowledge which has gone to the formation of these ideas entirely acquired after birth, or is there retained in the mind anything in the nature of impression or memory of that early period of existence in which gestation and birth were actually experienced? From the fact of the very general obliviscence which attends the first years of infancy, as well perhaps as from the relatively undeveloped state of the cerebrum in the newly born child, we might, with considerable show of reason, be inclined to disbelieve that any memory traces can be operative. On the other hand, the surprising fact of the sudden recovery in hypnosis, during psycho-analysis or otherwise, of early memories which had been entirely lost for many years, or again the fact that phantasies of birth or intra-uterine life seem sometimes to refer to details (_e. g._ the amniotic fluid or the different stages of labour) of which there is little opportunity to learn in ordinary life and which play but a small part, if any, in the average adult's conscious notions on these subjects, have made some writers hesitate to affirm too strongly the absolute impossibility of such operation. Again some may suggest that the knowledge which is mysteriously revealed in these phantasies may compel us to assume the existence of some such innate ideas as are perhaps involved in Jung's conception of the impersonal or racial Unconscious, according to which there are present in the unconscious mind certain materials (capable, apparently, of crystallisation into ideas of a certain degree of definiteness) which in their origin are assumed to be independent of personal experience, being, like our more fundamental instincts and tendencies, derived and inherited from a long line of ancestors. It is perhaps possible that more exact information on this important subject might be forthcoming as the result of careful investigations into such questions as the following: (1) To what extent (if at all) do children display--in dreams, phantasies or otherwise--knowledge as to the circumstances of their birth and pre-natal life which they could not possibly have obtained except from memory of their own past experience?