Abstract: For the controlled cooling of specimens which are at least partially of liquid form, especially biological specimens, it is important that crystallization at the freezing point takes place locally, without supercooling, and preferably with absorption of the latent heat of fusion. A cooling device which comprises at least one module which operates in accordance with the Peltier effect, with the "cold" faces of the modules connected by a conductive metal strip, has the specimen container in contact with the strip. The device is mounted in a working chamber which has its temperature/time profile controlled. At a temperature which is a predetermined amount above a given critical temperature for the specimen, e.g. its freezing point, the Peltier effect modules are energized to effect supplementary cooling at a local area, for example one end of the specimen.

Abstract: For the controlled cooling of specimens which are at least partially of liquid form, especially biological specimens, it is important that crystallization at the freezing point takes place locally, without supercooling, and preferably with absorption of the latent heat of fusion. At a temperature which is a predetermined amount above a given critical temperature for the specimen, e.g. its freezing point, a Peltier effect module is energized to effect supplementary cooling at a local area, for example one end of the specimen. The Peltier effect module and the specimen in its container supported in a sample holder are relatively movable. Preferably, the module is displaced, this being initiated by the insertion and removal of the sample holder, preferably by direct mechanical engagement.