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1 Small Step for a Squid, 1 Giant Leap for Biological Specimens

In September, the National Museum of Natural History (NMNH) in Washington, D.C. opened the Sant Ocean Hall. The hall, restored during the largest renovation in the museum's history, is home to 12 exhibits featuring to 674 specimens and models.

squid.jpgPerhaps the most important specimens in the hall are two giant squid. The 24-foot, 330-pound female is the most intact giant squid specimen on display anywhere in the world. She, and a smaller male, were caught by a group of deep-sea fishermen off the coast of northern Spain in 1995 and loaned to the NMNH by Coordinadora para el Estudio y la Protección de las Especies Marinas, a Spanish marine preservation organization.

The organization was keeping the squid in 400 gallons of formalin, a preservative fluid that is considered hazardous cargo and can only be transported commercially in quantities of 16 gallons or less. To get the squid stateside, the museum called the Navy, who accepted the task (dubbed "Operation Calamari") and brought the squid home in a U.S. Air Force C-17 cargo plane (pictured).

The Pickle of Pickling

In hindsight, getting the squid to the museum may have been the easy part. Preserving them posed an even bigger challenge.

There are some 1.5 billion biological specimens stored in institutions around the world (NMNH has about 124 million). "Wet" specimens, those that need to be stored in a preservative fluid, are usually (though not always) first fixed in a fixative solution, most commonly formaldehyde, which prevents the breakdown of proteins by forming chemical bonds and coagulating the contents of the specimen's cells into insoluble substances.

After fixing, a specimen is placed in a preservative fluid, which stabilizes it, prevents cell destruction and acts as its permanent home. The most common preservative fluids are alcohol (usually either ethyl alcohol or isopropyl alcohol), used since the 17th century, and formalin, a solution of formaldehyde diluted in water with some methyl alcohol added to prevent the formaldehyde from forming a solid mass, which was introduced in the 19th century.

Both of these preservatives present problems. Alcohol dehydrates specimens and leaches color from them, causing them to turn brown and then dirty white. Alcohol is also flammable; when Philadelphia's Mütter Museum was collecting specimens, one of the first donors insisted that his collection of fluid-preserved human organs needed be housed in a fireproof building. Formalin is better suited to preserve some specimens because of its fixative properties; it permeates a specimen's tissue and prevents it from decomposing. It's also less flammable than alcohol, but has a strong, unpleasant odor, is toxic and has been linked to certain types of cancer in animal tests.

Neither alcohol nor formalin retains specimens' true textures, and both preservatives allow specimens to move around in their containers, which can lead to breakages.

If you've seen more than a handful of fluid-preserved biological specimens, you know that some look much better than others. Somewhere, someone was doing something that preserved the specimen in excellent condition. Why don't all museums duplicate that technique for their collections? Unfortunately, in fluid preservation, most technique is the result of trial and error and records are rarely kept.

Where No Squid Has Gone Before

In addition to these challenges, Washington, D.C.'s fire marshal has significantly reduced the amount of flammable fluids that are allowed to be kept in public buildings since 9/11. The museum was authorized to use only 10 gallons of alcohol in the entire Sant Ocean Hall, while the female squid alone needed 1,200 gallons of fluid.

Formalin and alcohol were out, so the museum turned to Novec 7100 engineered fluid, developed by 3M, the diversified technology company. Novec, developed in the mid-1990s for cleaning electronics, isn't a preservative fluid, but a storage medium that forms a protective chemical envelope around specimens that have already been fixed in formalin. Novec is nonflammable, nontoxic and ozone-friendly. Its low water solubility keeps it from getting cloudy over time, and it doesn't drain color from specimens.

Novec has its share of problems, though. It evaporates easily, so specially designed jars with an extra-tight seal need to be used to contain specimens and the containers can't sit under lights that produce a lot of heat. Novec is also about 1.5 times denser than water, which means unrestrained specimens float to the top of their container, get exposed to air and decompose. Museum staff had to be careful to keep the squid submerged while also minimizing damage from any restraints they used. The squid are held down by a restraining bracket and reinforced with a metal screen, while broad transparent straps hold down the tentacles and distribute tension across them.

Novec's use in the squid exhibit is an ongoing experiment. For all their flaws, we know alcohol and formalin preserve specimens for a long time. No one knows how the squid will look in 20 or 30 years. Even while they're on display, the museum is taking samples of the squid's tissue and the storage fluid to see if the tissue is going through changes in cellular structure and if any compounds are leaching from the squid into the fluid. The museum is also breaking with preservation tradition by keeping meticulous records, starting with the squid's initial fixative injection in Spain and keeping pace with the tests they perform. The museum has said that every organization that donated specimens for the Sant Ocean Hall is eager to get plenty of data on Novec; if the squid are as intact a few decades down the line as they are now, Novec may become the fluid of choice for preservation. Here's lookin' at you, squid.

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Animals
Why Tiny 'Hedgehog Highways' Are Popping Up Around London
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Hedgehogs as pets have gained popularity in recent years, but in many parts of the world, they're still wild animals. That includes London, where close to a million of the creatures roam streets, parks, and gardens, seeking out wood and vegetation to take refuge in. Now, Atlas Obscura reports that animal activists are transforming the city into a more hospitable environment for hedgehogs.

Barnes Hedgehogs, a group founded by Michel Birkenwald in the London neighborhood of Barnes four years ago, is responsible for drilling tiny "hedgehog highways" through walls around London. The passages are just wide enough for the animals to climb through, making it easier for them to travel from one green space to the next.

London's wild hedgehog population has seen a sharp decline in recent decades. Though it's hard to pin down accurate numbers for the elusive animals, surveys have shown that the British population has dwindled by tens of millions since the 1950s. This is due to factors like human development and habitat destruction by farmers who aren't fond of the unattractive shrubs, hedges, and dead wood that hedgehogs use as their homes.

When such environments are left to grow, they can still be hard for hedgehogs to access. Carving hedgehog highways through the stone partitions and wooden fences bordering parks and gardens is one way Barnes Hedgehogs is making life in the big city a little easier for its most prickly residents.

[h/t Atlas Obscura]

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Big Questions
Where Should You Place the Apostrophe in President's Day?
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Happy Presidents’ Day! Or is it President’s Day? Or Presidents Day? What you call the national holiday depends on where you are, who you’re honoring, and how you think we’re celebrating.

Saying "President’s Day" infers that the day belongs to a singular president, such as George Washington or Abraham Lincoln, whose birthdays are the basis for the holiday. On the other hand, referring to it as "Presidents’ Day" means that the day belongs to all of the presidents—that it’s their day collectively. Finally, calling the day "Presidents Day"—plural with no apostrophe—would indicate that we’re honoring all POTUSes past and present (yes, even Andrew Johnson), but that no one president actually owns the day.

You would think that in the nearly 140 years since "Washington’s Birthday" was declared a holiday in 1879, someone would have officially declared a way to spell the day. But in fact, even the White House itself hasn’t chosen a single variation for its style guide. They spelled it “President’s Day” here and “Presidents’ Day” here.


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Maybe that indecision comes from the fact that Presidents Day isn’t even a federal holiday. The federal holiday is technically still called “Washington’s Birthday,” and states can choose to call it whatever they want. Some states, like Iowa, don’t officially acknowledge the day at all. And the location of the punctuation mark is a moot point when individual states choose to call it something else entirely, like “George Washington’s Birthday and Daisy Gatson Bates Day” in Arkansas, or “Birthdays of George Washington/Thomas Jefferson” in Alabama. (Alabama loves to split birthday celebrations, by the way; the third Monday in January celebrates both Martin Luther King, Jr., and Robert E. Lee.)

You can look to official grammar sources to declare the right way, but even they don’t agree. The AP Stylebook prefers “Presidents Day,” while Chicago Style uses “Presidents’ Day.”

The bottom line: There’s no rhyme or reason to any of it. Go with what feels right. And even then, if you’re in one of those states that has chosen to spell it “President’s Day”—Washington, for example—and you use one of the grammar book stylings instead, you’re still technically wrong.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

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