Health
Discover facts about health. Small discoveries that change the way you see familiar things.
Health
Early syringes used hollow bird feathers
In 17th-century experiments, a hollow quill provided a narrow tube and an animal bladder helped hold and push fluid. These improvised tools preceded the…
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Teenager Chester Greenwood invented fuzzy winter muffs
While ice skating in Maine in 1873, Chester Greenwood bent wire into ear coverings and asked his grandmother to sew beaver fur onto them. A practical…
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Your loofah is probably a dried gourd
The rough natural loofah comes from a member of the gourd family: the plant is dried and its fibrous interior becomes the scrubber. It’s a vegetable with a…
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Ancient Egyptians used copper tweezers
A pair of folded copper prongs could grip a hair and pull it from the skin. The tool looks ancient; the small, sharp sting of using it is remarkably familiar.
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Filthy contact lens cases are never replaced on time
Scrubbing can leave some buildup behind inside a lens case, where residue and microbes may linger. That is why an old case can still irritate your eyes even…
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When washing machines could trap your fingers
The rollers in early electric washers gripped wet fabric and squeezed out water. If a finger or loose clothing got pulled into that moving gap, the machine…
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Benjamin Franklin grew tired of swapping spectacles
Instead of changing spectacles whenever he switched tasks, Benjamin Franklin combined reading and distance lenses in one frame. The split let him use one part…
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Bose's noise-canceling headphones began with a disappointing flight
On a 1978 flight, Amar Bose found aircraft noise overwhelming the sound from the supplied headphones. He began working out how to counter the noise…
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A fluffy towel hides its advantage in the loops
The loops expose more cotton to water than a flat surface does. Narrow spaces between the fibers draw water in, while the pile gives it somewhere to go. What…
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Why airlines made sleep masks popular
Airlines began distributing fabric sleep masks in the 1950s to block cabin lights and the reading lights of nearby passengers. The mask solved a very specific…
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Why the eye doctor keeps asking one or two
The lenses in the phoropter bend light by different amounts, shifting the focus of the letters you see. When you choose “one” or “two,” you’re telling the…
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Handwashing transformed Semmelweis's maternity ward
In 1847 Vienna, Ignaz Semmelweis introduced chlorine-based handwashing before doctors examined women in labor. Deaths from childbed fever fell sharply. His…
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Ticks transmit Lyme disease primarily as nymphs
Young ticks are tiny enough to hide among hairs or blend into a speck of dirt, even after they attach. Because nymphs can spread Lyme disease and may be no…
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Dust mites trigger widespread indoor allergies
Dust mites are tiny arachnids that live indoors and feed on flakes of shed skin. Their waste contains allergens that can provoke sneezing, even when the…
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Polio once surged during summer
Polio spreads from person to person, often when traces of infected stool reach someone else's mouth. In summer, pools and crowded camps put many people…
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Why relying on corn caused pellagra
Corn contains niacin, but without alkaline lime treatment much of it remains unavailable for the body to use. A diet built on untreated corn can therefore…
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Scurvy killed more sailors than enemy fire
Vitamin C helps the body build collagen, the material that gives strength to connective tissue, including blood vessels and gums. Without it, that support…
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Leprosy is much harder to catch than its history suggests
Transmission generally requires prolonged, close contact with an untreated person, probably through droplets from the nose and mouth. A handshake or sitting…
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Norovirus needs only a tiny opening to spread
An infected person can shed billions of viral particles, while only a few are needed to cause illness. Contaminated hands, food, and surfaces can therefore…
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How iodized salt stopped goiters
The thyroid uses iodine to make its hormones, and a shortage can make the gland grow larger. Adding a little iodine to salt turned a routine seasoning into an…
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Zika virus was identified in the nineteen forties
Scientists first found Zika in a Ugandan forest in the 1940s, but finding a virus and recognizing it as a major threat are different things. For decades, it…
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The hidden slime inside restaurant ice machines
Ice machines have hidden surfaces that stay damp, and microbes can grow there if the parts aren't dismantled and sanitized. That pink film isn't on the ice;…
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Why rabies is almost always fatal after symptoms
Rabies can travel along nerves toward the brain, and symptoms such as headache or hydrophobia appear after the nervous system is involved. At that stage, the…
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How Florence Nightingale made statistics impossible to ignore
Nightingale's colored circular diagrams compared soldiers' deaths from wounds, disease, and other causes. The huge area representing preventable disease made…
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