John Elliot MD (1747 – 22 July 1787) was a physician and scientist in eighteenth-century London who was the first person to conjecture that different parts of the retina respond to particular colours of light. However, he was obsessed with Mary Boydell, niece[1] of the publisher John Boydell, and in 1787 was arrested for attempting to murder her. Although acquitted of attempted murder, he starved himself to death while awaiting trial for assault in Newgate Gaol.