Factoid—something that becomes accepted as fact, although it may not be true

‘It's not what people don't know that causes all the trouble—it's what they know that ain't so.’ Will Rogers, the cowboy philosopher

A few years ago, a fundraising campaign by the Parkinson's Disease Society depicted Dr James Parkinson as a man without a face, for the sound reason that no portrait of him is known to exist. All we have is a description by his friend and fellow paleontologist Dr Gideon Mantell, who …