A Temperature Control System for Small Biological Preparations, Displaying Relatively Fast Heating and Cooling Capability

An apparatus is described with which it is possible to warm and cool the main duct of rabbit submaxillary gland in 10cc Ringer solution between 0°C and 50°C. The apparatus can be used for any small biological preparations such as muscles, nerves, etc. The heating and cooling is performed by a peltier element together with its control unit. Temperature is measured with a Cu-Const. thermocouple-with the reference placed in melting ice. The absolute accuracy of the temperature is ±0.5°C but reproducibility is within 0.10C. Speed of warming up for a large temperature change (AT) is 0.8°C/s. Cooling is-stower, i.e., 0.4°C/s. For AT 5°C the speed of warming up is about 0.60°C/s and the cooling rate in this case varies between 0.5°C/s and 0.16°C/s depending upon starting temperature. Full details are given about the construction of the control unit and the perfusion chamber in which the main duct is mounted. Some modifications are discussed with which it is also possible to use the system for flat biological preparations. The use of the apparatus as a programmable temperature system or as a temperature function generator is also discussed.