Eine einfache Technik der extrem schnellen Abkühlung größerer Gewebestücke

TLDR: In this article, a pair of tongs are used to compress large tissue pieces and organs of animals to a thin layer and can thus be frozen in a fraction of a second.

Abstract: 1. A pair of tongs was designed the mouth of which consists of two blocks of a metal of high thermal conductivity (aluminum). Prior to use the metal is cooled in liquid air or nitrogen. With this tool large tissue pieces and whole organs of animals can be compressed in situ to a thin layer and can thus be frozen in a fraction of a second. The fall in temperature was measured with a thermocouple and was recorded with a loop oscillograph. Measurements of the cooling velocity in liquid air and in isopentane of −150°C were carried out for comparison. 2. The cooling process in the compressed tissue was analyzed with the aid of the theory of heat conduction, and the heat conduction equation holding for the present system was derived. It yields values for velocity of cooling which agree well with the experimental data in the temperature range 38°2-0°C. The cause of the deviation at lower temperatures is discussed. 3. Instructions are given for the estimation of the time required to cool down the central layer of the tissue held in the tongs to any specified temperature.