The mystery wasn't solved for more than 100 years, until 17-year-old Bill Martin heard about the glowing wounds while visiting the battle site. After talking to his mom, Phyllis (who happened to be a microbiologist with the USDA, Martin and his friend Jon Curtis began a series of experiments to determine if the glowing could have been caused by a bacteria in the soil. After researching which weather and soil conditions at Shiloh could be hospitable to bacteria that glow in the dark, their work proved successful, except that the bacteria they were studying, Photorhabdus luminescens, couldn't survive in the heat of the human body. But because it was April in Tennessee, it was cold: soldiers waiting two days for medical attention likely had hypothermia. This would have cooled the bodies enough for the angel's glow to persist. And unlike many pathogens that turn simple wounds deadly, this particular microbe likely sped up the healing process.