This week on The Exchange, how the medical victories of the past can help us move forward in dealing with the coronavirus. Today, we hear some little-known stories of medical and scientific innovations that doubled the human lifespan in the 20th century. We talk with the force behind the new PBS Series Extra Life: The Science of Living Longer, Steven Johnson. The series begins this week. Also, science is getting closer to giving people expanded, and some say, superhuman abilities. We talk with