Professor Arsenius Jigger was a wizard and an author specialising in Potions and Defence Against the Dark Arts, having written: Magical Drafts and Potions, Potion Opuscule, and The Essential Defence Against the Dark Arts. Arsenius Jigger was also, at an unknown point, a professor of Defence Against the Dark Arts at Hogwarts School of Witchcraft and Wizardry. A shop in Diagon Alley bears the name Slug and Jiggers, and may belong to him.