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This is Scientific American 60-Second Science. I'm Christopher Entalyatta.

Nearly 350 years ago, the Dutch scientist Antoniv on Leuwenhoek

scraped some white stuff off his teeth, as thick as if it were batter, he wrote,

and peered at it under one of his handmade microscopes. What he saw was alive. He described it as

many very little living animacules, very prettily moving, the biggest of which shot through the

water or spittle like a pike does through the water. What he had discovered in the plaque from

his teeth, the animacules, that was bacteria. And before von Leuwenhoek's observations of bacteria,

nobody could have discovered bacteria because they didn't have the optical resolution.

Lombard von Eik is a material scientist at the Delft University of Technology in the Netherlands.

He says some of von Leuwenhoek's microscopes could magnify things more than 200 times,

and contemporaries like Robert Hook in England, who'd written a book full of microscopic observations,

they were stunned by his findings. Robert Hook actually spent quite some effort trying to

discover why was Antoniv Reuwenhoek so skilled and what kind of mysterious ways of producing the

lenses made him able to see for the first time bacteria. But von Leuwenhoek wasn't eager to reveal

the secrets behind the hundreds of microscopes he built. Some people have explicitly asked him about

the lenses, and he never said anything about it. It's still a big mystery how these lenses were

...