In still another case it may be definitely ascertained, without the aid of dream interpretation, that the dream contains elements from childhood; that is, if it be a so-called _perennial_ dream, which being first dreamt in childhood, later appears again and again after adult age has been reached. I may add a few examples of this sort to those already familiar, although I have never made the acquaintance of such a perennial dream in my own case. A physician in the thirties tells me that a yellow lion, about which he can give the most detailed information, has often appeared in his dream-life from the earliest period of his childhood to the present day. This lion, known to him from his dreams, was one day discovered _in natura_ as a long-forgotten object made of porcelain, and on that occasion the young man learned from his mother that this object had been his favourite toy in early childhood, a fact which he himself could no longer remember. If we now turn from the manifest dream content to the dream thoughts which are revealed only upon analysis, the co-operation of childhood experiences may be found to exist even in dreams whose content would not have led us to suspect anything of the sort. I owe a particularly delightful and instructive example of such a dream to my honoured colleague of the “yellow lion.” After reading Nansen’s account of his polar expedition, he dreamt that he was giving the bold explorer electrical treatment in an ice field for an ischæmia of which the latter complained! In the analysis of this dream, he remembered a story of his childhood, without which the dream remains entirely unintelligible. When he was a child, three or four years old, he was listening attentively to a conversation of older people about trips of exploration, and presently asked papa whether exploration was a severe illness. He had apparently confused “trips” with “rips,” and the ridicule of his brothers and sisters prevented his ever forgetting the humiliating experience.