How Can You Swap Kidneys?

A chain of 70 different people was organized so 35 donors gave a kidney to 35 strangers. Some academics have proposed swapping other organs, such as parts of a liver. This has only happened once, when a tenacious tenager read an academic paper and thought that these swops were already happening. She started calling up hospitals and saying, how can you do this? And they did and and the operation went through successfully.