Since medieval times the leech has been used to cure everything from fever to possession by evil spirits. Now doctors have brought it into the 21st century with a robotic version that can repair damaged hearts. The tiny device slides across the surface of the still-beating heart, delivering treatment without the need for open heart surgery. Once inside the body, the Heart-Lander can inject drugs, attach pacemaker leads and may even be able to destroy damaged tissue. Outside the body, the surgeon controls the two-ounce robot using a joystick and monitors its progress via a TV screen. Its size and flexibility give it several advantages over current surgical techniques and believe it could even be used without a general anaesthetic, cutting down the length of time patients spend in hospital.