The psychoanalysis of individuals teaches us that the most precocious impressions, collected at a time when the child is still only stammering, provoke one day, without even resurfacing in the conscious, obsessive effects. If, to the perfect analogy which exists between the formation of a dream and that of a neurotic symptom, we add the rapidity of the transformation which makes the dreamer an awake and reasonable man, we will acquire the certainty that neurosis rests, too, on an alteration of the relations normally existing between the different forces of the psychic life.