We all know about supposed hidden drug messages in Beatles and Rolling Stones songs. But what of J.K. Rowling’s kid-friendly Harry Potter books? You heard it here first: Muggles — the series’ word for non-magic folk — was a rather improper noun in jazz-era slang. ”It was a common term for a reefer,” says John P. Morgan of the pro-marijuana group NORML, adding that Louis Armstrong wrote a 1928 song with the name. Still, Morgan doesn’t suspect any inside dope: ”I can’t believe the [British] author had any idea.” Neither can her U.S. publisher. ”It’s pure happenstance,” says Kris Moran of Scholastic. ”She uses it as a derivative of the term mug, meaning fool.” But put this in your pipe: Rowling has said she found some of her character names in a book on herbs. And who’s her hero? Harry Pot-ter. Whoa.