Sexual Anomalies and Perversions  

"Incidentally, he also had an affair with his wife's sister, with whom he went on long journeys. The sister seems to have been the very antithesis of the Marquis de Sade, and was, in fact what is today described as "vamp." The two sisters were the originals of the two characters Justine and Juliette in de Sade's famous novel."--Sexual Anomalies and Perversions (1938) by Norman Haire

“One of the first pioneers in the systematic investigation of sexual aberrations was Dr. Kahn, a Ruthenian physician who, though living in straitened circumstances, with few opportunities for research, nevertheless enriched the science of sexual pathology by many important discoveries. Another pioneer who deserves recognition was August Forel, who in his monumental work analyzed sexual aberrations with the same objectivity and attention to detail that he applied to his work on ants. Krafft-Ebing's Psychopathia Sexualis is still an inexhaustible storehouse of cases, to which modern investigators return again and again, in spite of the immense amount of more recent material. Havelock Ellis in his classic work dealt with the physiological determination of sadomasochistic phenomena, while Moll, Schrenk-Notzing, Fere, and Bloch, the great sexual physiologists of the late nineteenth century, were already able to lay the foundations of a general theory of the sexual sciences."--Sexual Anomalies and Perversions (1938) by Norman Haire