Two years ago, I managed volunteer guides at a local museum. A college student named Jack collided with the museum like a meteor on a chilly fall day, took a tour, and decided to become a tour guide himself. All who knew him sensed Jack was living life at high speed.    Jack soon became a favorite at the museum. He was funny and insightful, and we became friends. One day, Jack sheepishly told me of his bipolar disorder. He was on a fast train to death, he said, and taking his life was his destiny. I asked Jack if he was medicated and had a therapist, and I tried to offer another perspective. Jack put me in touch with his [...]