characteristics of Leonardo which remained unexplained through psychoanalytic effort are first, his particular tendency to repress his impulses, and second, his extraordinary ability to sublimate the primitive impulses. The impulses and their transformations are the last things that psychoanalysis can discern. Henceforth it leaves the place to biological investigation. The tendency to repression, as well as the ability to sublimate, must be traced back to the organic bases of the character, upon which alone the psychic structure springs up. As artistic talent and productive ability are intimately connected with sublimation we have to admit that also the nature of artistic attainment is psychoanalytically inaccessible to us. Biological investigation of our time endeavors to explain the chief traits of the organic constitution of a person through the fusion of male and female predispositions in the material sense; Leonardo's physical beauty as well as his left-handedness furnish here some support. However, we do not wish to leave the ground of pure psychologic investigation. Our aim remains to demonstrate the connection between outer experiences and reactions of the person over the path of the activity of the impulses. Even if psychoanalysis does not explain to us the fact of Leonardo's artistic accomplishment, it still gives us an understanding of the expressions and limitations of the same. It does seem as if only a man with Leonardo's childhood experiences could have painted Monna Lisa and Saint Anne, and could have supplied his works with that sad fate and so obtain unheard of fame as a natural historian; it seems as if the key to all his attainments and failures was hidden in the childhood phantasy of the vulture.