* This, it may be said, requires a corresponding duration of experience; but, as an argument for this mysterious power lurking in our nature, I may remind the reader of one phenomenon open to the notice of every body, viz. the tendency of very aged persons to throw back and concentrate the light of their memory upon scenes of early childhood, as to which they recall many traces that had faded even to themselves in middle life, whilst they often forget altogether the whole intermediate stages of their experience. This shows that naturally, and without violent agencies, the human brain is by tendency a palimpsest.