Dr. Jekyll and Mr. Hyde.

"It was on the moral side, and in my own person, that I learned to recognise the thorough and primitive duality of man; I saw that, of the two natures that contended in the field of my consciousness, even if I could rightly be said to be either, it was only because I was radically both; and from an early date . . . I had learned to dwell with pleasure, as a beloved daydream, on the thought of the separation of these elements."