The researchers found that they were able to store their rat livers for three days, then transplant them into healthy rats. All six rats who received those three-day-old livers survived the entire duration of the study, which lasted three months. An additional 12 rats received supercooled livers that had been stored for four days. Seven of those little guys survived for three months. On the other hand, all of the rats died whose liver transplants had been treated in the usual way, but stored for three days—much longer than the 24 hours that researchers have previously found is tops for rat liver transplants.