Angel’s glow refers to the unexplained radiance observed in the wounds of soldiers during the American Civil War. It is believed that this glow was caused by the presence of a bacteria called Photorhabdus luminescens. This bacteria resides in the intestines of a type of roundworm commonly found in Shiloh, Tennessee, where the phenomenon was first reported.
The night was chilly, dark, and filled with danger. Across the muddy battlefield, numerous soldiers lay injured, desperately in need of medical attention. Blood flowed from their wounds, increasing the risk of deadly infections. However, in the midst of this grim scene, the wounds of a select few emitted a mysterious blue glow, as if some magical force was pulling them back from the brink of death.
The Battle of Shiloh
Although it may sound like a fairy tale, this is actually a legend from the Battle of Shiloh. Also known as The Battle of Pittsburg Landing, this conflict is infamous for being one of the bloodiest battles of the American Civil War. The chaos erupted on April 6, 1862, in Shiloh, Tennessee, and lasted for two days, resulting in the loss of 23,000 lives.
The Battle of Shiloh (Photo Credit: Everett Collection/Shutterstock)
Angel’s Glow: A Mysterious Iridescent Glow
After more than 48 hours, medical personnel arrived at the location, where physicians, nurses, and survivors all described a strange blue-ish glow emanating from certain soldiers’ injuries. Those who treated these soldiers also documented that individuals with these enigmatic glowing wounds had a higher likelihood of survival compared to others.
Lieutenant Ambrose Bierce personally observed the occurrence and subsequently achieved renown as a celebrated writer. He recounted the battle, expressing, “Divine celestial beings were present, unseen, amidst the valiant soldiers dressed in both blue and gray, peacefully resting in eternal slumber within the Chickamauga woods.”
The strange occurrence, known as ‘Angel’s Glow’, has perplexed medical professionals and scientists since its discovery in the American Civil War. It took almost 140 years and the curiosity of two high school students to finally uncover the truth behind this peculiar mystery!
In 2001, Bill Martin, a 17-year-old student, visited the Shiloh battleground with his family, where he learned about the wounds that emitted a glowing light.
Since his childhood, Bill had a keen interest in science and was fascinated by his mother’s profession. His mother, Phyllis Martin, worked as a microbiologist at the USDA Agricultural Research Service, where she conducted research on luminescent bacteria residing in soil. Drawing connections, Bill inquired whether bioluminescent bacteria could be responsible for the phenomenon known as the ‘Angel’s Glow’.
Similar to any competent scientist, she requested him to conduct an experiment to verify the theory. He collaborated with his friend and fellow enthusiast of science, Jon Curtis, with the aspiration of unraveling the enigma.
They initiated their project by conducting preliminary research. They started by acquiring knowledge about various bacterial strains that emitted light and cross-checked this information with historical records to confirm their potential presence in Shiloh.
During their search, one specific type of bacteria, Photorhabdus luminescens, caught their attention.
Inside a fat wax moth corpse, numerous small nematodes were discovered (Photo Credit: Peggy Greb/Wikimedia Commons)
The Cause of the Angel’s Glow: Bacteria Infection
In the muddy fields of Shiloh, Tennessee, a specific type of bacteria was found residing within the digestive system of small worms known as nematodes.
These tiny worms are parasites and feed on insects that are located in the thick mud. They penetrate the body of the insect and establish their residence within the insect’s blood vessels.
Once the nematode reaches the bloodstream of the insect, it eventually expels the bacteria. The bacteria then releases a powerful chemical mixture that eliminates not only the host insect but also any other microorganisms that may be inside it.
When there are no other organisms to compete with, the bacteria and the nematode can eat, grow, and reproduce without any obstacles until the insect body is completely emptied! Surprisingly, after this process, the nematodes consume the bacteria again, which have multiplied enough to emit a vibrant bluish-green light.
Researchers believe that the luminosity attracts a greater number of insects, thus facilitating the nematode in locating its subsequent host.
Phyllis Martin had conducted research on the potential use of P. luminescens as a biocontrol agent to combat crop-damaging insect pests. She was aware of the mutualistic relationship between nematodes and bacteria.
Regarding the soldiers, it was likely that their open wounds were infected by various insects and microorganisms, which were the main source of their illness. Bill and Jon suggested that the nematodes had also entered the soldiers’ wounds from the muddy ground.
When the bacteria were released into the bloodstream, its toxin killed all other microbes, preventing fatal wound infections. The bacteria multiplied and produced a bluish-green glow on the wound. The glowing wounds helped the soldiers survive. The medics during the Civil War did not understand the antibiotic nature of the bacterial toxin because the scientific world was unaware of the medical potential of bacteria at that time. It was not until Alexander Fleming’s discovery of penicillin in 1928 that the power of antibiotics was revealed.
To determine that the bacteria caused the angel’s glow, Bill and John faced two major problems. The first problem was that the bacteria could not survive at the normal temperature of a human body. However, they discovered that the evening temperatures in Tennessee during early April were quite low and it had been unusually rainy during the battle. These conditions allowed the bacteria to grow and glow inside the wounds. They also had to prove that the bacteria were responsible for faster wound healing. Existing research showed that the bacteria produced an antibiotic that killed off other microbes, preventing fatal infections. The bacteria also possessed enzymes and toxins that were deadly to insects.
Summary
Recently, researchers have discovered that P. luminescens, a bacterium, produces lumicins, which are bacteriocins that can kill other bacterial strains. Phyllis Martin is utilizing this characteristic of P. luminescens to combat Colorado potato beetles, pests that harm agricultural crops. The glowing bacteria, hidden within the nematode genus Heterorhabdus, can effectively control this pest beetle. Therefore, it serves as a viable alternative to chemical pesticides for farmers.
Colorado potato beetle (Photo Credit: Aleksandr Rybalko/Shutterstock)
Previously, it was believed that glow-in-the-dark wounds were merely myths. However, Bill and Jon’s scientific explanation has revealed that the mysterious glow might have been real. In fact, their discovery earned them first place at the 2001 Intel International Science and Engineering Fair!
During the Battle of Shiloh in April 1862, the soldiers faced harsh conditions and were wounded. Stranded in muddy, rain-soaked fields, over 16,000 soldiers were at risk of infection. Thankfully, the right bacterium, a bioluminescent bacteria, illuminated their wounds and saved them from death. While the soldiers credited the angels, it was actually the tiny bioluminescent bacteria that brought them back to life.