Simply make them take you in on the footing of a lodger

"Simply make them take you in on the footing of a lodger." As she leaves, she remarks that he will have to cope with her niece "of minor antiquity". Obligingly, the anti-hero explains the dastardly task at hand. Jarvis is obsessed with the poet Jeffrey Aspern, whom he believes to have been in love with the now nearly 100-year-old Miss Havisham-like Juliana. 'Abracadabra' is at the Wellcome Institute, London NW1 to 26 October (0171-611 8888). "What are you up to?" What indeed? Biographical hound and literary scholar Henry Jarvis has inveigled the suspicious, resplendently dressed Mrs Prest into gaining entrance to the shuttered Venetian home of the sequestered Misses Bordereau and she and we want to know why.

They form a language of the imagination, and, especially in a medium like opera, they make new moves possible. A composer recasts existing notes and transforms time signatures and plays with given rhythms, so a librettist can attempt to translate the old spells and figures that have proved effective in the past: the star-crossed lovers, the cross-dressed heroine, the cross patriarch, and the crossings of destinies in any life.n Music Theatre Wales premieres 'In the House of Crossed Desires' at the Everyman Theatre 6 and 10 July as part of the Cheltenham International Festival of Music (booking: 01242 227979). It would have been possible to write the part of this "disreputable hag" as one of the many beaten-up homeless women who sit on the pavements of Kentish Town and the Strand, but the strength of the conventions rooted in both opera and fairy-tale means that she could be established as a person with tremendous economy of means; and, as Helena says in A Midsummer Night's Dream, that most enchanted of all the fairy plays, "Things base and vile, holding no quantity / Love can transpose to form and dignity."Philip Larkin's gift for the acerbic epigram has memorably stigmatised "dipping into the myth kitty"; but its contents aren't so easily put in a box and shut up and the key thrown away, as his metaphor suggests; they're parts of thought, invisible, stealthy, potent. It is anti-historical to argue that authentic, original versions should be retained.

The trick is rather to re-tell them in fresh ways in order to ignite the special pleasure of unconscious recognition for the audience in question - as Carol Ann Duffy triumphantly achieves with her verse version of Grimms' Tales staged last year at the Young Vic to the delighted thrills and squeals of laughter of school parties.In the House of Crossed Desires attempts to transform some of the recurring motifs of fairy-tale: the vicious old woman jailer, with her threats and her whip, takes centre stage in the part of Greasy Joan, but she is translated, too - if the desired alchemy of music, performance and words works - to become a person with her own past of lost loves, loneliness, and desperate choices. The disguise means that certain themes can be tackled which, stripped, might be censored out: that donkey business in The Dream covers a multitude of sins without ducking the issue of sex.But censorship, as everyone knows, has frequently struck the fairy-tale just the same. Rapunzel, in the Grimm brothers' earliest version, describes how the heroine pulls up the prince by her hair into the tower and enjoys his company for a while until, one day, she asks the Old Witch, "How is it that my clothes are getting so tight?" So the old woman realises that her ward has been up to no good, and cuts her hair and smashes the tower and blinds the prince and other such openly coded acts. But the Grimms became uneasy about the explicit character of Rapunzel's plight, and they changed her question to "Why are you, Old Mother, so much heavier than the prince I pull up by my hair when you're not looking?" Thus making a complete ninny of Rapunzel and a nonsense of the fairy-tale, draining it of its traditional warning against the appeal of passing wolves.Fairy-tales are open to transformation, and the Grimms were working in the fine storytelling mode of adapting material to suit their chosen hearers and readers: in their case, ideals of middle-class urban family decorum prevailed.