Among the various items in the collection of Hiroshima University’s Research Institute for Radiation Biology and Medicine are two glass specimen jars, each maybe six inches tall, and each filled with a clear liquid and an amorphous brown blob that one might at first mistake for a crumpled grocery bag. They are all that remain of stage actress Midori Naka. Naka, known in Japan for her work in the shingeki drama style, was 36 years old when the atomic bomb nicknamed Little Boy exploded near her. She was not killed…