God knocked St. Paul off his horse but He chose to convert me with a gruff man,a severed foot, and the face of a little child. It was 1962. I was fifteen, an atheist, and a first-time Red Cross volunteer. With bag lunch in hand, I stepped into the hospital's tiny pathology lab and introduced myself to the stern-faced man who ran it.He could have been the twin brother of Sonny Liston,the soon-to-be heavyweight champion of the world. "I'm Tyler," he said. "Put your lunch in that refrigerator." I opened the refrigerator, leaned forward, and gasped. There, just where I was about to place my lunch, lay a severed human foot!Tyler guffawed. Most days Tyler joked around as we prepared polyps, cysts, appendices, tumors, and other surgically-removed bits and pieces for examination by the staff pathologist. One morning, however, he cracked no jokes. Just before the pathologist arrived, he said "John, I don't want you here this morning. The doctor's got t...