This piece of hair is a rare example of royal biological material in a public collection. Henry Wellcome bought the hair at auction in 1927 but very little is known about it. Recent tests on the hair may have discovered the reason for the King's episodes of so-called madness. The hair was found to have an unexpectedly high concentration of arsenic. Heavy metals such as arsenic are known to exacerbate a hereditary condition called porphyria, which can lead to mental disturbances.