Nine Things About Silk That Sound Made Up (But Aren't)

Scratch the surface of silk and you find espionage, mythology, medicine and one very determined worm. Here are nine true things worth knowing — and worth repeating at dinner.

Some facts are too good to keep to yourself. You learn one and immediately want to tell someone. Silk is full of them. Here are nine of our favourites. Make a cup of tea first.

1. One cocoon holds a thread up to 1,600 metres long

The silkworm is a small creature with an enormous output. Each cocoon it spins is a single unbroken filament that can run to 1,600 metres. That is longer than fifteen rugby fields laid end to end. One worm. One thread. It is hard not to be a little impressed.

2. Silkworms can no longer survive without us

We have bred the domesticated silkworm, Bombyx mori, for about five thousand years. Somewhere along the way it forgot how to be wild. It cannot fly. It cannot find its own food. It has lost any instinct to hide from predators. It depends on human care entirely, which is either the high point or the low point of the whole human-insect arrangement.

3. China made leaking the secret punishable by death

For roughly three thousand years, the Chinese court guarded the method of making silk with real ferocity. Sending silkworm eggs abroad was a capital offence. So was explaining the process to a foreigner. The secret held for millennia. The penalty, you imagine, helped.

4. A princess smuggled silkworm eggs out in her headdress

When a secret is kept at the cost of lives, someone bold usually comes along to break it. In the first century AD, a Chinese princess heading west to marry a Central Asian king hid silkworm eggs in her elaborate headdress. The border guards searched the obvious places and apparently stopped there. Silk-making took root in Central Asia soon after.

5. The Romans named China after silk before they ever met the Chinese

Rome could not get enough silk, and could not work out where it came from. The senate debated transparent silk gowns and what they said about public decency. Roman men kept wearing it regardless. When formal contact with China was finally made, the Romans called the country Serica, from their word for silk. To Rome, China was simply the land of the silk people.

6. The “Silk Road” was named 1,877 years after it opened

The routes linking China with Central Asia, Persia and eventually Europe ran for about two thousand years before anyone gave them a collective name. The phrase “Silk Road” was coined in 1877, by a German geographer named Ferdinand von Richthofen. The traders, pilgrims and armies who had used the roads for centuries got along fine without the branding.

7. Silk contains eighteen amino acids that are good for your skin

Silk is not just smooth. Its proteins, mostly fibroin, contain eighteen amino acids — the same building blocks found in human skin. That is why the two get along so well. The proteins help skin hold moisture and bring mild antimicrobial and antioxidant properties. This is not marketing. It is biochemistry. The fabric feels gentle on your skin because, in a real sense, it speaks the same language.

8. Spider silk is being trialled for surgery and drug delivery

Mulberry silk comes from the humble silkworm, but the wider silk family is more ambitious. Spider silk is stronger than steel by weight and elastic enough to absorb serious force. Researchers are now testing it for surgical sutures, wound healing, nerve repair and controlled drug delivery. The spider, true to form, seems entirely unbothered by the attention.

9. Silk is FDA-approved as a medical biomaterial

Here is the one that stops people. The same fabric draped down a runway or smoothing the line of a blouse is also classified by the US Food and Drug Administration as a safe biomaterial for medical use. Trials at the University of Colorado are studying silk fibroin nanofibres for skin rejuvenation, looking at how they encourage collagen in the deeper layers of skin. The luxury, it turns out, goes all the way down.

Silk has been with us for nearly five thousand years. It has outlasted empires, crossed deserts, and quietly seen off every fabric that came along to replace it. On this evidence, that seems about right.