Libraries and whores are not natural bedfellows. Yet in the Wellcome Library on Euston Road you can work your way though more loose women than Genghis Khan on his gap year. The centre holds the world's foremost collection of tart cards -- those colourful adverts that decorate London's phone boxes. Stephen Lowther is in charge of the smutty stash, which forms part of the library's medical ephemera collection. The holdings comprise single sheet publications......