For Bulwer, gesture was the only from of speech that was inherently natural to mankind, and he saw it as a language with expressions as definable as written words. He describes some recognisable hand gestures, such as stretching out hands as an expression of entreaty or wringing them to convey grief, alongside more unusual movements, including pretending to wash your hands as a way to protest innocence, and to clasp the right fist in the left palm as a way to insult your opponent during an argument. Although Bulwer’s theory has its roots in classical civilisation, from the works of Aristotle, he was inspired by hundreds of different works, including biblical verses, medical texts, histories, poems and orations, in order to demonstrate his conclusions.