Psychoanalysis is applied to a modern ritual, whose symbolic elements are extracted and subjected to standard interpretation. Such a procedure reveals that the compulsive habit of 'knocking on wood' temporarily abolishes the fear of castration or death, by discharging in a symbolic, and therefore innocuous form, preoedipal strivings of an ambivalent oral character. The juxtaposing of an abstract of two analytic hours testifies to the correctness and pertinence of the symbolic interpretation employed. It does so after the fashion of a clinical experiment, in that the patient, who associates to a sexual ritual of undoubtedly preoedipal character, furnishes each and every one of the symbolic expressions in question. A fragment of another patient's analytic hour is appended which shows the same symbol aggregate as the first, although in an anal mode of expression.