What did Leeuwenhoek use that enabled him to see bacteria?

Antonie van Leeuwenhoek used simple microscopes with carefully made lenses to magnify tiny objects. The greater magnification let him observe bacteria, which were too small to see with the unaided eye. Heating foods and liquids was later used by Pasteur to study microbes, not by Leeuwenhoek to see them.

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