TOKYO (AFP) - Japanese researchers said Tuesday they had developed a self-propelled remote controlled capsule endoscope that can swim through the digestive tract. They have succeeded in capturing images inside a persons stomach and colon using the tadpole-shaped capsule as a first step toward its clinical application, the scientists said. It is the first time a self-propelled endoscope has successfully moved from one part of the digestive tract to another and shot images inside the colon, the team said. The device, nicknamed the Mermaid, is about one centimetre (0.4 inches) in diameter and 4.5 (1.8 inches) long and has magnetic driving gear that allows for precise control of its direction and location. Doctors use a joystick to control the capsules movements, watching them on a monitor screen. It can be swallowed for examination of the stomach or inserted rectally for the colon.