"I was very handsome and made the best impression on myself. We took a car (sharing the expenses). Ricchetti was terribly nervous, I was quite serene thanks to a small dose of cocaine, although his success was assured, and I had every reason to fear ridicule. (...) This is how I have performed (or rather how the cocaine has performed) and I am very satisfied."

Freud, letter to Martha dated January 20, 1886.

During the 1880s, the young Freud, who had not yet explored the labyrinths of the unconscious, tried to make a name for himself by publishing studies on erythroxylon coca, a plant from which an alkaloid, cocaine, was made and whose properties he praised. To these studies, which the French-speaking reader will find here in a new translation, we enclose some letters to Martha Bernays, his future wife, which shed light on Freud's intimacy with the drug.