ANTONY VAN LEEUWENHOEK.

This is an essay about the Dutch linen-draper of the seventeenth century who made more than 500 microscopes and used them to observe the tail of an eel, the sting of a bee, the nose of a louse, the brain of a fly, the spinning apparatus of a spider, the bacteria from his own mouth, etc., and who wrote enthusiastic letters to the Royal Society of London carefully describing what he saw.