An adequate account of the development of the dragon-legend would represent the history of the expression of mankind's aspirations and fears during the past fifty centuries and more. For the dragon was evolved along with civilization itself. The search for the elixir of life, to turn back the years from old age and confer the boon of immortality, has been the great driving force that compelled men to build up the material and the intellectual fabric of civilization. The dragon-legend is the history of that search which has been preserved by popular tradition: it has grown up and kept pace with the constant struggle to grasp the unattainable goal of men's desires; and the story has been constantly growing in complexity, as new incidents were drawn within its scope and confused with old incidents whose real meaning was forgotten or distorted. It has passed through all the phases with which the study of the spreading of rumours or the development of dreams has familiarized students of psychology. The simple original stories, which become blended and confused, their meaning distorted and reinterpreted by the rationalizing of incoherent incidents, are given the dramatic form with which the human mind invests all stories that make a strong appeal to its emotions, and then secondarily elaborated with a wealth of circumstantial detail. This is the history of popular legends and the development of rumours. But these phenomena are displayed in their most emphatic form in dreams.