The history of sexual crime is of secondary Importance compared with the philosophy which enables us to define the interrelations of abstract sexual criminality with those peculiar anthropological phases of sexual character which, while abnormal, are not necessarily illicit. There are some men, for instance, in whom the sex-element occupies so large a share of life that they can hardly be judged by the standards which apply to others, in whom the same element is small, or almost entirely absent; what would be a sexual crime in one community, custom may render quite non-criminal in another; and hence arise the difficulty, and not infrequently the injustice, of enforcing arbitrary legal penalties as they apply to sexual offences en bloc.