Guest episode: In this episode we introduce you to a part of our bodies that was invisible to Western scientists until about five years ago; it’s called "the interstitium," a vast network of fluid channels inside the tissues around our organs that scientists have just begun to see, name, and understand. Along the way we look at how new technologies rub up against long-standing beliefs, and how millions of scientists and doctors failed to see what was right in front (and inside!) of their noses. We also find out how mapping the anatomy of this hidden infrastructure may help solve one of the fundamental mysteries of cancer, and perhaps provide a bridge between ancient and modern medicine. Learn more about your ad choices. Visit podcastchoices.com/adchoices