A versatile light microscope heating stage for biological temperatures

A light microscope heating stage suitable for biological temperatures is described. A novel feature of the design is the use of cupro-nickel foil heaters (0.1 mm thick). With a temperature sensor mounted on the slide clip and a temperature controller unit, this apparatus maintains a temperature of 310 K with a precision of 0.1 K. The apparatus is inexpensive, reliable, not confined to use with one microscope and does not interfere significantly with the stage movement or optical alignment.