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Gas Cryostat (Jung)

Mount Sinai Pathology Lab · Health Sciences

A metal instrument with a curved, tapering form. The metal surface of the instrument has a blue and grey galvanized steel finish. At one side of the instrument are two clamps that are presumably meant to secure the instrument to the edge of a sturdy workbench. This would place the instrument at an orientation perpendicular to the one shown in the photos to this entry.

At the top of the instrument is a hand operated microtome mechanism and a sample chuck (also called a platen). The chuck can be advanced relative to the microtome mechanism using a crank at the base of the instrument. The rate of advance is adjusted using a switch at the base of the instrument. The setting is shown in a dial that is read through a window at the front of the instrument. There is no microtome blade in the blade clamp.

Near the chuck is a flattened metal orifice that is likely the release point for the pressurized C02 gas used in the sample freezing process.

A removable black plastic tray can be set on the top surface of the instrument, presumably to capture sections cut from a sample using the microtome.

Two large valve handles protrude from one side of the instrument, their ends pointing in opposite directions.

A black tube protrudes from the base of the instrument. This may attach to a tank of pressurized CO2 gas.

A second clear tube also emerges from the base. This is crimped using a metal clamp near its end.

Accession Number: 2023.MTS.6

Alternative Name:

Primary Materials: Iron Alloy


Dimensions (cm): Height = 55, Width = 26, Length = 26.


This gas cryostat was used to freeze and section tissue for mounting and staining fresh tissue. Samples were coated with a viscous glycerol gel and placed on the round chuck. Pressurized CO2 gas from an attached cylinder was released over the sample, freezing it through the cooling effect of the Joule–Thomson process. The frozen sample was then cut into thin sections using the attached microtome. Sections would then be mounted on microscope slides and dyed in order to facilitate diagnosis.


This artifact is in good cosmetic condition. There are small patches of dirt, and small areas of chipped paint, at various points on its outer surface. Some metal surfaces have superficial rust, for instance the arm that manipulates the microtome mechanism. There is no blade in the microtome mechanism.

Associated Instruments:

Manufacturer: Jung AG, Heidelberg, Germany.

Date of Manufacture: c. 1960s.


The Mount Sinai Pathology Lab collection was transferred from a display case on the 6th floor of Mount Sinai Hospital (600 University Ave. Toronto, On) over several days in mid-December 2020.

Additional Information and References:

Louis B. Wilson. (1905). “A Method for the Rapid Preparation of Fresh Tissues for the Microscope.” JAMA : the Journal of the American Medical Association XLV, no. 23: 1737–1737.

Anthony A. Gal. (2005). “The Centennial Anniversary of the Frozen Section Technique at the Mayo Clinic.” Archives of Pathology & Laboratory Medicine (1976) 129, no. 12 (2005): 1532–35.

Historical Notes:

The modern technique of frozen sample preparation was developed by brothers William Charles Mayo, both medical doctors, at the Mayo Clinic of Rochester, Minnesota in the first decade of the 20th century. (See Mayo 1905.) The technique greatly increased the speed of diagnosis through biopsy over the earlier method which required relatively lengthy preparation of the sample tissue.

The Spencer Freezing Microtome was developed to facilitate the process. This artifact is a development of that instrument. (See Gal 2015.)

By the 1970s, gas cryostats had been developed with the sample and microtome housed in a refrigerated box. This is now the standard instrument.

  • Donated to UTSIC