Light microscopy of a thin-sectioned freeze-substituted suspension of human sperm cryopreserved in conventional straws (0.25ml capacity). The cryoprotectant used was glycerol/egg yolk. Ice was nucleated within the straw at -7°C. The sample was then cooled at 10°C per minute to -100°C and then transferred to liquid nitrogen. Light microscopy shows numerous sperm cells embedded within the freeze concentrated material. For higher magnifications of this sample see the next pages.
