"There are some things best left to imagination," replied the Principal dryly. "For instance, there would be no need to dispense with forks, and let you hold mutton bones with your fingers at dinner, in order to demonstrate fourteenth-century manners, nor to bleed you every time you had a toothache, to test ancient practices of medicine. If you're so very anxious to skip a few hundred years, I have, in an old Herbal, a prescription to cure 'swimming in ye heade and such like phantasies'. It consists mainly of pounded snail-shells, mixed with boiled tansy and snippings from the hair of an unbaptized infant born between Easter and Michaelmas. Any one who wishes has my permission to try it."