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11 Squeaky-Clean Facts About Spit

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Though most people find the thought of saliva rather disgusting, spit plays a vital role in our lives. It allows us to comfortably chew, swallow, and digest. It fights off bacteria in our mouths and elsewhere, and leads the mouth’s bold fight against cavities. Here are 11 facts that might have you reconsidering that unsung hero of bodily fluids: spit. 

1. IT’S MOSTLY WATER. 

Saliva consists of about 99 percent water. The other 1 percent is made up of electrolytes and organic substances, including digestive enzymes and small quantities of uric acid, cholesterol, and mucins (the proteins that form mucus). 

2. THERE’S A MEDICAL STANDARD FOR HOW MUCH YOU SHOULD DROOL. 

Healthy individuals accumulate between 2 to 6 cups of spit a day. That’s without stimulation from activities like eating or chewing gum, which open the spit floodgates [PDF]. 

3. SALIVA PRODUCTION HAS A CIRCADIAN RHYTHM.

Your body typically produces the most saliva in the late afternoon, and the least at night. Salivation is controlled by the autonomic nervous system (much like your heartbeat), meaning it’s an unconscious process. 

4. THERE ARE FIVE DIFFERENT KINDS OF SPIT.

Salivation has five distinct phases, most triggered by the passage of food through the body. Not all of them are a good thing. The first type of salivation is cephalic, the kind that occurs when you see or smell something delicious. The buccal phase is the body’s reflexive response to the actual presence of food in the mouth (which aids in swallowing). The oesophageal involves the stimulation of the salivary glands as food moves through the oesophogus. The gastric phase happens when something irritates your stomach—like when you’re just about to puke. The intestinal phase is triggered by a food that doesn’t agree with you passing through the upper intestine. 

5. IT CAN BATTLE BACTERIA. 

There’s a reason the phrase “lick your wounds” came about. Spit is full of infection-battling white blood cells. And, according to a 2015 study in the journal Blood, neutrophils—a type of white blood cell—are more effective at killing bacteria if they come from saliva than from anywhere else in the body. So adding saliva to a wound gives the body a powerful backup as it fights off infection. 

6. IT KEEPS YOU FROM GETTING CAVITIES.

The calcium, fluoride, and phosphate in saliva strengthen your teeth. Spit also fights cavity-causing bacteria, washes away bits of food, and neutralizes plaque acids, reducing tooth decay and cavities. That’s why chewing gum gets dentists’ stamp of approval—chewing increases the flow of saliva, thus protecting your oral health. 

7. YOU NEED IT IF YOU WANT TO TASTE ANYTHING. 

Saliva acts like a solvent for tastes, ferrying dissolved deliciousness to the sites of taste receptors. It also keeps those receptors healthy by keeping them from drying out and protecting them from bacterial infection. Many people who have dry mouth (xerostomia) find their sense of taste affected by their oral cavity’s parched conditions. Because many medications have dry mouth as a side effect, scientists have developed artificial saliva sprays that mimic the lubrication of real spit. 

8. SWAPPING SPIT EXCHANGES MILLIONS OF BACTERIA. 

A 10-second kiss involves the transfer of some 80 million bacteria, one study found. 

9. PEOPLE AREN’T BORN DROOLING. 

Babies don’t start drooling until they’re two to four months old. Unfortunately, they also don’t really know what to do with their spit. They don’t have full control of the muscles of their mouth until they’re around two years old, so they can’t really swallow it effectively. Which is why we invented bibs. 

10. STRESS CAN LEAVE YOU SPIT-LESS. 

The body’s fight-or-flight response is designed to give you the energy and strength needed to overcome a near-death experience, like, say, running into a bear, or, more common in the modern age, giving a big presentation at work. Your blood pressure goes up, the heart beats faster, and the lungs take in more oxygen. This is not the time to sit around and digest a meal, so the digestion system slows down production, including that of saliva

11. A LACK OF SPIT WAS ONCE USED AS AN ADMISSION OF GUILT. 

In some ancient societies, saliva was used as a basic lie detector. In ancient India, accused liars had to chew grains of rice. If they were telling the truth, they would have enough saliva to spit them back out again. If someone was lying, their mouth would go dry and the rice would stick in their throat. 

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Billions of Cockroaches Are Bred in China to Create a ‘Healing Potion’
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Insectophobes would probably agree that any place that breeds billions of cockroaches a year is akin to hell on Earth.

That place actually exists—in the Sichuan Province city of Xichang—but China's government says it's all for a good cause. The indoor farm is tasked with breeding 6 billion creepy-crawlies a year to meet the country's demand for a special "healing potion" whose main ingredient is ground-up roaches.

While there are other cockroach breeding facilities in China that serve the same purpose, the one in Xichang is the world's largest, with a building "the size of two sports fields," according to the South China Morning Post.

The facility is reportedly dark, humid, and fully sealed, with cockroaches given the freedom to roam and reproduce as they please. If, for any odd reason, someone should want to visit the facility, they'd have to swap out their day clothes for a sanitized suit to avoid bringing pollutants or pathogens into the environment, according to Guangming Daily, a government newspaper.

The newspaper article contains a strangely poetic description of the cockroach farm:

"There were very few human beings in the facility. Hold your breath and (you) only hear a rustling sound. Whenever flashlights swept, the cockroaches fled. Wherever the beam landed, there was a sound like wind blowing through leaves. It was just like standing in the depths of a bamboo forest in late autumn."

Less poetic, though, is the description of how the "miracle" potion is made. Once the bugs reach maturity, they are fed into machines and ground up into a cockroach paste. The potion claims to work wonders for stomach pain and gastric ailments, and according to its packaging, it has a "slightly sweet" taste and a "slightly fishy smell."

The provincial government claims that the potion has healed more than 40 million patients, and that the Xichang farm is selling its product to more than 4000 hospitals throughout China. While this may seem slightly off-putting, cockroaches have been used in traditional Chinese medicine for thousands of years.

Some studies seem to support the potential nutritional benefit of cockroaches. The BBC reported on the discovery that cockroaches produce their own antibiotics, prompting scientists to question whether they could be used in drugs to help eliminate bacterial infections such as E. coli and MRSA.

In 2016, scientists in Bangalore, India, discovered that the guts of one particular species of cockroach contain milk protein crystals that appear to be nutritious, TIME reports. They said the milk crystal could potentially be used as a protein supplement for human consumption, as it packs more than three times the energy of dairy milk.

"I could see them in protein drinks," Subramanian Ramaswamy, a biochemist who led the study, told The Washington Post.

However, as research has been limited, it's unlikely that Americans will start to see cockroach smoothies at their local juice bar anytime soon.

[h/t South China Morning Post]

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Why a Train Full of New York City Poop Was Stranded in Alabama for Two Months
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Residents of Parrish, Alabama probably aren't too fond of New Yorkers right now. That’s because the town is currently home to a full trainload of poop courtesy of the Big Apple, as Bloomberg reports. Some 200 shipping containers of treated sewage have been stuck in Parrish for more than two months while the town takes landfill operators to court.

New York City doesn't keep its own sewage sludge to itself, and it hasn't for decades. In the 1980s, New York City was dumping its "biosolids"—the solids left over from sewage treatment, i.e., your poop—into the Atlantic Ocean, where it settled on the bottom of the sea floor in a thick film stretching over 80 square nautical miles. When the government banned the practice of dumping waste straight into the ocean, the city had to get creative, finding a way to get rid of the 1200 tons of biosolids produced there every day.

Enter the poop train. As a 2013 Radiolab episode taught us (we highly recommend you listen for yourself), treated sludge was eventually shipped out to other states to use as fertilizer in the 1990s. After farmers in Colorado began noticing better growth and fewer pests in the fields they grew with New York City's finest sewer sludge, growers in other states began clamoring to take the big-city poop by the train-full, too. That tide has turned, though, and now no one wants the city's poop. Because of the cost of running the program, the train to Colorado stopped in 2010.

Now, biosolids are instead shipped to landfills upstate and in places like Georgia, Ohio, and Pennsylvania, according to The Wall Street Journal. And Alabama. For more than a year, the Big Sky landfill near Parrish has been accepting New York City biosolids, and the locals who have to deal with trainloads of rotting waste aren’t happy.

Normally, the sludge would be loaded onto trucks and then driven the last stretch to get to the landfill. But Parrish and its nearby neighbor of West Jefferson aren't interested in playing host to those messy poop transfers anymore. As the two towns take the landfill operators to court over it, the trains are stuck where they are, next to Parrish's Little League baseball fields. The trainload of sludge is blocked from either being sent to the landfill or back to New York City. While the city has stopped shipping more waste to Big Sky, it essentially said "no takebacks" regarding what they've already sent south. Short of a legal decision, that poop isn't moving.

Needless to say, the residents of Parrish would really, really like to resolve this before summer hits.

Update: Parrish residents can officially breathe easy. The last of the sludge has now been removed from the town, and Big Sky has ended its operation there, according to a Facebook post from Mayor Heather Hall. The containers that remain have been emptied of their smelly cargo and will be removed sometime before Friday, April 20.

[h/t Bloomberg]

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