Medicine: Pneumatic Arm

Most artificial arms are based on a simple principle: mechanical linkage carries muscle power to the artificial limb, from either the shoulder or the stump muscles. Convinced that mechanically transmitted muscle power was not the best solution, Professor Siegmund Weil and Technician Otto Häfner of Heidelberg University set out to develop a light, small and more efficient substitute. This week, after seven years of research, they were busy teaching amputees how to use their invention: an artificial arm operated by pressurized gas.

Made of wood, metal and rubber, the arm is powered by a flat, easily hidden carbon-dioxide container linked by rubber...