MacMillan compares the complete Freud-Fliess correspondence, edited by Masson and published in 1985, with the previous incomplete edition. He examines four areas of historical interest. 1) Janet's determination—that hysterical symptoms represent ideas—meshed with formulations of Hughlings Jackson, and was utilized by Freud in theorizing with Breuer that hysterical symptoms result from abnormal modes of discharging surplus excitation. 2) Freud's "dissociation" from Breuer's theoretical chapter in Studies on Hysteria occurred because Breuer was not willing to agree that all hysteria is derived from sexual fantasies. 3) Freud's hypothesis that hysteria has a sexual etiology was not based primarily on his observations of hysterical patients; its main source was Freud's generalization of a similar etiological hypothesis about the causes of the actual neuroses. 4) Gattel's statistical investigation of the actual neuroses, which implied an improbable high rate of childhood seduction, could well have been a factor in Freud's abandonment of the childhood seduction theory.