After he was paralyzed by polio at age 6, Paul Alexander was confined for much of his life to a yellow iron lung that kept him alive. He was not expected to survive after that diagnosis, and even when he beat those odds, his life was mostly constrained by a machine in which he could not move.But the toll of living in an iron lung with polio did not stop Mr. Alexander from going to college, getting a law degree and practicing law for more than 30 years. As a boy, he taught himself to breathe for minutes and later hours at a time, but he had to use the machine every day of his life.He died…