The researchers came across this phenomenon almost by accident. After having little success transplanting donor liver cells into a recipient's damaged liver, they began searching for other areas of the body where the cells could survive, injecting them at different places in mice with liver disease. While most of the rodents died, those that had injections in their abdomen survived. "When we opened the animals, we found between 20 to 30 very small livers throughout their body where the lymphatic system is, particularly the lymph nodes," says Lagasse. In subsequent experiments, they inserted the liver cells directly into the lymph nodes of mice, pigs and dogs, finding this transformed the organs into fully functioning livers. "We don't know exactly what happens," says Lagasse. "[It] is something very extraordinary, to an extent a little bit science fiction."