Revival of Spermatozoa after Vitrification and Dehydration at Low Temperatures

THE effect on spermatozoa of vitrification at temperatures of −79° C. and below has been studied by several authors. Human spermatozoa appear to be the most resistant; a substantial proportion may show good motility on thawing after even prolonged vitrification. Revival is far better when semen is frozen in bulk than when minimal amounts in capillary tubes are used1. No explanation of this result is yet forthcoming, but it would appear that rapidity of freezing is less important than the avoidance of surface effects.