Why Some Civil War Soldiers Glowed in the Dark

By the spring of 1862, a year into the American Civil War, Major General Ulysses S. Grant had pushed deep into Confederate territory along the Tennessee River. In early April, he was camped at Pittsburg Landing, near Shiloh, Tennessee, waiting for Maj. Gen. Don Carlos Buell’s army to meet up with him.

On the morning of April 6, Confederate troops based out of nearby Corinth, Mississippi, launched a surprise offensive against Grant’s troops, hoping to defeat them before the second army arrived. Grant’s men, augmented by the first arrivals from the Ohio, managed to hold some ground, though, and establish a battle line anchored with artillery. Fighting continued until after dark, and by the next morning, the full force of the Ohio had arrived and the Union outnumbered the Confederates by more than 10,000.

The Union troops began forcing the Confederates back, and while a counterattack stopped their advance it did not break their line. Eventually, the Southern commanders realized they could not win and fell back to Corinth until another offensive in August (for a more detailed explanation of the battle, see this animated history).

All told, the fighting at the Battle of Shiloh left more than 16,000 soldiers wounded and more 3,000 dead, and neither federal or Confederate medics were prepared for the carnage.

The bullet and bayonet wounds were bad enough on their own, but soldiers of the era were also prone to infections. Wounds contaminated by shrapnel or dirt became warm, moist refuges for bacteria, which could feast on a buffet of damaged tissue. After months marching and eating field rations on the battlefront, many soldiers’ immune systems were weakened and couldn’t fight off infection on their own. Even the army doctors couldn’t do much; microorganisms weren’t well understood and the germ theory of disease and antibiotics were still a few years away. Many soldiers died from infections that modern medicine would be able to nip in the bud.

A Bright Spot

Some of the Shiloh soldiers sat in the mud for two rainy days and nights waiting for the medics to get around to them. As dusk fell the first night, some of them noticed something very strange: their wounds were glowing, casting a faint light into the darkness of the battlefield. Even stranger, when the troops were eventually moved to field hospitals, those whose wounds glowed had a better survival rate and had their wounds heal more quickly and cleanly than their unilluminated brothers-in-arms. The seemingly protective effect of the mysterious light earned it the nickname “Angel’s Glow.”

In 2001, almost one hundred and forty years after the battle, seventeen-year-old Bill Martin was visiting the Shiloh battlefield with his family. When he heard about the glowing wounds, he asked his mom - a microbiologist at the USDA Agricultural Research Service who had studied luminescent bacteria that lived in soil - about it.

“So you know, he comes home and, 'Mom, you're working with a glowing bacteria. Could that have caused the glowing wounds?’” Martin told Science Netlinks. “And so, being a scientist, of course I said, ‘Well, you can do an experiment to find out.’”

And that’s just what Bill did.

He and his friend, Jon Curtis, did some research on both the bacteria and the conditions during the Battle of Shiloh. They learned that Photorhabdus luminescens, the bacteria that Bill’s mom studied and the one he thought might have something to do with the glowing wounds, live in the guts of parasitic worms called nematodes, and the two share a strange lifecycle. Nematodes hunt down insect larvae in the soil or on plant surfaces, burrow into their bodies, and take up residence in their blood vessels. There, they puke up the P. luminescens bacteria living inside them. Upon their release, the bacteria, which are bioluminescent and glow a soft blue, begin producing a number of chemicals that kill the insect host and suppress and kill all the other microorganisms already inside it. This leaves P. luminescens and their nematode partner to feed, grow and multiply without interruptions.

As the worms and the bacteria eat and eat and the insect corpse is more or less hollowed out, the nematode eats the bacteria. This isn’t a double cross, but part of the move to greener pastures. The bacteria re-colonize the nematode’s guts so they can hitch a ride as it bursts forth from the corpse in search of a new host.

The next meal shouldn’t be hard to find either, since P. luminescens already sent them an invitation to the party. Just before they got got back in their nematode taxi, P. luminescens were at critical mass in the insect corpse, and scientists think that that many glowing bacteria attract other insects to the body and make the nematode’s transition to a new host much easier.

A Good Light

Looking at historical records of the battle, Bill and Jon figured out that the weather and soil conditions were right for both P. luminescens and their nematode partners. Their lab experiments with the bacteria, however, showed that they couldn’t live at human body temperature, making the soldiers’ wounds an inhospitable environment. Then they realized what some country music fans already knew: Tennessee in the spring is green and cool. Nighttime temperatures in early April would have been low enough for the soldiers who were out there in the rain for two days to get hypothermia, lowering their body temperature and giving P. luminescens a good home.

Based on the evidence for P. luminescens’s presence at Shiloh and the reports of the strange glow, the boys concluded that the bacteria, along with the nematodes, got into the soldiers’ wounds from the soil. This not only turned their wounds into night lights, but may have saved their lives. The chemical cocktail that P. luminescens uses to clear out its competition probably helped kill off other pathogens that might have infected the soldiers’ wounds. Since neither P. luminescens nor its associated nematode species are very infectious to humans, they would have soon been cleaned out by the immune system themselves (which is not to say you should be self-medicating with bacteria; P. luminescens infections can occur, and can result in some nasty ulcers). The soldiers shouldn’t have been thanking the angels so much as the microorganisms.

As for Bill and Jon, their study earned them first place in team competition at the 2001 Intel International Science and Engineering Fair.

Hard Sell: A History of the Pet Rock

Amazon
Amazon

You may have heard the story of the Pet Rock, the Mexican beach stone that could be purchased in bulk for less than a penny, retailed for $3.95, and made inventor Gary Dahl a millionaire during a kind of novelty gift hysteria in late 1975. But Dahl didn’t really get rich off of the rock.

He got rich off of a cardboard box.

Dahl was working as a freelance advertising copywriter in California that year when, while having drinks at a bar with friends, the conversation turned to the destructive nature of pets. Dogs and cats ruined furniture. Worse, they required constant attention, from being walked to being fed to cleaning up after them. Dahl said that he didn’t have to worry about any of that because he had a “pet rock.”

It was, of course, a joke. And it got a laugh. But Dahl decided there could be more to it than that. He went home and began writing an owner’s manual for this hypothetical pet rock, which detailed how best to handle it, the tricks it could perform (“play dead” being the most popular), and how it could remain a faithful companion due to its “long life span.” The gag was not so much the rock itself but the way it was presented. In addition to the manual, Dahl conceived of a cardboard box with air holes that resembled the kind used by pet shops. It also bore a passing resemblance to a McDonald's Happy Meal container.

 

Dahl's motivation in making a serious effort to monetize his pet rock idea was due in large part to his precarious financial situation at the time—he was struggling to keep up with his bills. He recruited George Coakley and John Heagerty, two colleagues, to come on as investors. They both signed on, with Coakley investing $10,000—a not-inconsiderable sum in 1975, especially when the intention was to sell virtually worthless rocks.

The Pet Rock packaging is pictured
Wikimedia Commons // Public Domain

Dahl, however, knew what he was marketing. Like chattering teeth, the Hula Hoop, and other fads, the Pet Rock was the beneficiary of good timing. Vietnam had ended but Watergate was still fresh; the country’s mood was slightly downcast, and Dahl believed people would see the inane nature of the Pet Rock and recognize the humor of it. He boxed the rocks with the manual and packed them in excelsior, which may be best known as comic book legend Stan Lee’s catchphrase but also means a softwood shaving pile meant for protecting fragile items. The rocks were purchased from a local sand and gravel company, which sourced them from Mexico’s Rosarita Beach. Dahl debuted the rock at a gift show in San Francisco in August of 1975, then waited for a reaction.

He got one. People understood the appeal right away and he began taking orders. Neiman Marcus wanted 1000 rocks. Bloomingdale’s later signed on. Newsweek did a story with a picture, which spread the word. Dahl had retail and media credibility for what was superficially a nonsense product. His bar joke was turning into a national phenomenon.

When the holiday season arrived, Dahl estimated he was selling up to 100,000 Pet Rocks a day. Ultimately, he would sell between 1.3 and 1.5 million of them within a period of just a few months. Coakley made $200,000 back on his initial $10,000 investment. Dahl gifted both Coakley and Heagerty with Mercedes. Making 95 cents in profit on each Pet Rock sold, Dahl earned over $1 million. He launched his own firm, Rock Bottom Productions, which was itself another joke. “You’ve reached Rock Bottom” is how the receptionist answered their phone.

 

The fad did not last—by definition, they’re not designed to—but Dahl was satisfied. His two investors were not; they "claimed they had received too small a share of the profits" and later sued Dahl for more revenue. After a judgment in the investors' favor, Dahl wrote them a six-figure check.

The Pet Rock is pictured
Amazon

There were attempts to prolong the life of the rock by offering a Bicentennial version in 1976—it had the American flag painted on it—and mail-order college degrees for them. Dahl sold Pet Rock T-shirts and Pet Rock shampoo. There were also copycat gifts, since Dahl could not really patent a rock. (He might have been able to obtain a utility patent because of the rock’s particular purpose as a companion, but he did not.) The humor was transient, however, and people had moved on.

Dahl had other ideas. There was the Official Sand Breeding Kit, which claimed to provide guidance on growing sand, and Canned Earthquake, which consisted of a coffee can that had a wind-up mechanism that caused it to jump around on a table. Neither was particularly successful. Dahl’s real passion, though, was buying and renovating a bar in Los Gatos, which he named Carrie Nation’s Saloon.

This was not without its problems, as people who believed they had the next Pet Rock would often stop by the bar to try and secure an audience with Dahl for his insight. Many times, their idea consisted of packaging bull or elephant excrement. There were also proposals to market a pet stick. Dahl had no patience for these inventors, believing the Pet Rock could not be duplicated. Later, he went back to advertising after taking what he described as an “eight-year vacation” following the success of his project.

The Pet Rock can still be found online, though it’s no longer Dahl’s business. He died in 2015. Of the unsold rocks he had left over at the end of the fad, he was indifferent. If they didn’t sell, he said, he would just use them to repave his driveway.

Submarine Expedition Reveals Parts of the Titanic Have Fully Decayed

NOAA/Institute for Exploration/University of Rhode Island
NOAA/Institute for Exploration/University of Rhode Island

In 1985, oceanographers Robert Ballard, Jean-Louis Michel, and their crew located the wreck of the RMS Titanic at the bottom of the Atlantic Ocean. Images of the shipwreck have since become as iconic as photographs of the ocean liner taken before the 1912 tragedy. But the ruin's time in the ocean is limited. As part of an upcoming documentary, a crew of scientists carried out the first manned expedition to the wreck in 14 years and discovered the Titanic is rapidly decaying, BBC reports.

After it sank, the Titanic settled in two parts on the seafloor about 370 miles off the coast of Newfoundland, Canada. Most of the wreck is still intact, but a lot has changed since 2005, when it was last visited by a human-occupied submersible.

While working on a film for Atlantic Productions London, an exploration team from Triton Submarines visited the wreck five times over eight days and discovered that entire sections of the ship have disappeared. The starboard side of the officer's quarters has deteriorated, and the captain's bathtub is totally gone. The deck house on the same side and the sloping lounge roof of the bow are also on the brink of collapse, according to the crew.

Unlike other artifacts and historic sites, there's no way to preserve the wreckage of the Titanic for future generations. Churning ocean currents, corrosive salt, and metal-eating bacteria will continue to break down the steel behemoth until it becomes part of the sea. Some experts estimate that by 2030, it's likely that no part of the wreck will remain.

Whether that projection is off by years or decades, these findings suggest that every new team that visits the Titanic may find something different than the team before them. On this most recent expedition, the Triton Submarines exploration team was able to film the wreck in 4K for the first time. That footage may end up being some of the last ever captured of many elements of the ship.

[h/t BBC]

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