Humour, according to Max Eastman, is “the instinct for taking pain playfully”; and he was certainly right about comics. In their early days, the comics were all about funny pain: sadistic pranks, outrageous mishaps, disproportionate reprisals. Head injuries were especially popular, especially when inflicted by a cop. One of the many modern refinements absent from old comics was our attitude towards police brutality. Police are always brutal, and the thud of nightstick against skull provides not just the soundtrack but the punchline for thousands of last panels. The single most frequent image in old comics is not an alley cat …