Having fried your leeks in butter, form them into a poultice and apply it to your backside. No, not Heston Blumenthal’s latest wheeze: instead the cure for piles advocated by William Buchan, 18th-century author of Domestic Medicine, now republished as Can Onions Cure Ear-ache? (Bodleian Library, £14.99). The new title gives you a clue to Buchan’s general style (poultice again).