can only be scored by a touch with the tip of the blade; hits with the flat of the blade are ignored. The same is true of wit; witticisms are surgical strikes. The American author Ambrose Bierce was a master of witty precision, once demolishing a rival's work in a review that read in its entirety: "The covers of this book are too far apart." Bierce's Devil's Dictionary is a curmudgeonly, commonplace book of his own misanthropic definitions: "corporation: an ingenious device for obtaining individual profit without individual responsibility"; "misfortune: the kind of fortune that never misses"; and "alone: in bad company". No one wielded the weapon of wit better than the dastardly Franois, Duc de la Rochefoucauld. This 17th-century French aristocrat specialised in the darker aphoristic arts, mercilessly dissecting the more unsavoury precincts of the human heart: "Old people are fond of giving good advice; it consoles them for no longer being able to set a bad example." "The desire of the man is for the woman, but the desire of the woman is for the desire of the man." And "In the adversity of even our best friends, we always find something not wholly displeasing." Yet even the duke cushioned his blows with black humour: "How comes it that our memories are good enough to retain even the minutest details of what has befallen us, but not to recollect how many times we have recounted them to the same person?" Aphorisms are like vaccines: they inject a little