Wait not in vain

OVER the course of an average winter North American wood frogs, Rana sylvatica, may freeze solid several times. They are able to get away with this by replacing most of the water in their bodies with glucose mobilised from stores in their livers. That stops ice forming in their tissues as temperatures drop. When things warm up again, the frogsicles thaw out, with no evident ill effects.

What frogs do without thinking, human researchers are trying, with a great deal of thinking, to replicate. The prize is not the freezing and reanimation of entire people—that idea is somewhere between a fantasy and a fraud—but the long-term preservation of organs for transplant. According to the World Health Organisation, less than 10% of humanity’s need for transplantable organs is being met. The supply has fallen as cars have become safer and intensive-care procedures more effective, and part of what supply there is is lost for want of an instantly available recipient. Cooled, but not frozen, a donated kidney might last 12 hours. A donated heart cannot manage even that span. If organs could be frozen and then thawed without damage, all this would change. Proper organ banks could be established. No organs would be wasted. And transplants that matched a patient’s requirements precisely could be picked off the shelf as needed.