"A very elementary exercise in psychology, not to be dignified by the name of psycho-analysis, showed me, on looking at my notebook, that the sketch of the angry professor had been made in anger. Anger had snatched my pencil while I dreamt. But what was anger doing there? Interest, confusion, amusement, boredom--all these emotions I could trace and name as they succeeded each other throughout the morning. Had anger, the black snake, been lurking among them? Yes, said the sketch, anger had."