Somewhere, I think in Northanger Abbey, Jane Austen says of the world that circumstances change and opinions alter. It seems that, in some respects at least, she was only half right. In England last year a group of gay men were arrested and charged with assault because of the sadomasochism they practiced. None of those involved had made a complaint, since none had anything to complain about. The Crown, however, viewed it differently and decided to prosecute, because inflicting pain, whether at the invitation of those to whom it is meted out or not, is an activity that quite simply ought not to