DOES CRYOGENIC TEMPERATURE DESTROY STRUCTURE?
There are Arctic reptiles such as frogs and salamanders that can survive very low temperatures with a large part of their body water converted to ice. They can do this because their livers manufacture a large amount of glycerol. Glycerol is antifreeze: it reduces ice formation and lowers freezing point. Other arctic insects & reptiles use sugars as antifreeze. Such antifreeze substances are called cryoprotectants. A cryoprotectant can make water solidify the way glass hardens: with no crystal formation. Freezing-damage to cells is due to the formation of ice-crystals, which grow between cells and crush them — or the creation of toxic hypertonic solutions. Evidence of freezing damage can be seen by freezing and rewarming lettuce or strawberries. In 1949 it was discovered that glycerol can be used to protect bull sperm against freezing injury. A year later, the same techniques were successfully applied to red blood cells. Since that time large industries have developed around the cryopr
