Note 23 — LEONARDO DA VINCI

For a corroboration of this improbable sounding assertion see the "Analysis of the Phobia of a Five-year-old Boy," Jahrbuch für Psychoanalytische und Psychopathologische Forschungen, Bd. I, 1909, and the similar observation in Bd. II, 1910. In an essay concerning "Infantile Theories of Sex" (Sammlungen kleiner Schriften zur Neurosenlehre, p. 167, Second Series, 1909), I wrote: "But this reasoning and doubting serves as a model for all later intellectual work in problems, and the first failure acts as a paralyzer for all times."