William F. Rall
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The Modern Laboratory
William F. Rall
A cryobiologist who helped show that an embryo could be cooled into glass, with no ice at all.
A student of ice. William F. Rall spent his working life on one problem: what happens to living cells as they freeze and thaw. In the late 1970s and early 1980s he published with Peter Mazur on how glycerol protects frozen red blood cells and how water leaves a mouse egg as it cools. He also worked with Christopher Polge on how warming rate affects frozen mouse embryos.
No ice at all. At the American Red Cross cryobiology laboratory in Bethesda, Maryland, he and Gregory Fahy asked whether an embryo could avoid ice completely. In 1985 they reported in Nature that mouse embryos survived well after being held at minus 196°C in a solution so concentrated that it set into a clear glass. This was vitrification, and it is the method most IVF laboratories now use.
Proving it in living young. At the Medical Research Council unit in Carshalton, near London, he worked with David Whittingham. In 1987 they reported that eight-cell mouse embryos vitrified this way developed into 98 normal fetuses and young after transfer.
Banking embryos. He later joined the Veterinary Resources Program at the National Institutes of Health in Bethesda, where he froze embryos to preserve rat and mouse models of human disease. He also worked with Smithsonian scientists on embryos of zebrafish and other species.
He was elected a Fellow of the Society for Cryobiology, which now lists him among its deceased Fellows. Every vitrified egg and embryo carries a little of his work.
Also see: Gregory M. Fahy, Peter Mazur, David Whittingham, Stanley Leibo
About the sources
- Society for Cryobiology. Fellows of the Society for Cryobiology (William Rall, Bethesda, listed under Deceased Fellows), societyforcryobiology.org, accessed October 2026.
- Rall WF, Schmidt PM, Lin X, Brown SS, Ward AC, Hansen CT. Factors affecting the efficiency of embryo cryopreservation and rederivation of rat and mouse models. ILAR Journal 2000;41(4):221–227 (affiliation: Veterinary Resources Program, NIH). PMID 11123182.
- Hagedorn M, Kleinhans FW, Wildt DE, Rall WF. Chill sensitivity and cryoprotectant permeability of dechorionated zebrafish embryos. Cryobiology 1997. PMID 9160996.
- Rall WF, Wood MJ, Kirby C, Whittingham DG. Development of mouse embryos cryopreserved by vitrification. Journal of Reproduction and Fertility 1987;80(2):499–504. PMID 3656282.
- Rall WF, Fahy GM. Ice-free cryopreservation of mouse embryos at -196 degrees C by vitrification. Nature 1985;313(6003):573–575 (affiliation: American Red Cross Cryobiology Laboratory, Bethesda). PMID 3969158.
- Rall WF, Polge C. Effect of warming rate on mouse embryos frozen and thawed in glycerol. Journal of Reproduction and Fertility 1984. PMID 6363690.
- Rall WF, Mazur P, Souzu H. Physical-chemical basis of the protection of slowly frozen human erythrocytes by glycerol. Biophysical Journal 1978. PMID 667300.
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Compiled with AI-assisted research and checked against the original sources. Not yet peer-reviewed. Corrections are warmly welcomed.
