In a previous work I tried to show how a parent's traumatic experiences can weigh on the following generations, approaching these phenomena in terms of introjection and incorporation. Traumatized patients who inherited such burdens suffered a block of their vital abilities, and are then challenged to later acquire the ability to symbolize what had remained unelaborated by previous generations. Accidental impressions, foreign to the patient's story, possibly a result of a certain pre-understanding of the patient's unconscious communications, emerge in countertransference and may reveal hitherto unexpressed dimensions, dissociated psychic areas of the patient.