In the early 20th century, a premature baby was considered as good as dead. But Dr. Martin Couney — who wasn’t actually a doctor — made it his mission to save these babies by putting them neonatal incubators. And Couney had a flair for the dramatic. He would put incubated babies on display at Coney Island, and at World’s Fairs, where people could see them — IF they paid a quarter. We talk to Dawn Raffel about her new biography, “The Strange Case of Dr. Couney: How a Mysterious European Showman Saved Thousands of American Babies.”