Abstract: A freezing apparatus for bringing samples of biological tissue in contact with a block of sapphire that is chilled to 15.degree. K. has a toggle linkage that controls movement of a plunger carrying a biological tissue sample into contact with a cold surface of sapphire, and minimizes rebound by slowing the rate of approach of the tissue sample toward the cold surface to a velocity of substantially zero at contact. An outer box of plexiglass is used to limit the formation of condensates on the surface of the sapphire, and the specimen carrier includes a miniature moist chamber that protects the specimen from drying before moving it toward the surface. The moist chamber is removed just before operation of the freezing apparatus. The toggle linkage provides repeatability of results with minimum setup time between insertion of samples, and substantially reduces rebounding and vibration that retards the rate of freezing of the specimen.