Van Leeuwenhoek · Microbes
Is anything alive in a single drop of water?
That time, that place
He kept a draper's shop in Delft. Using a magnifier to count threads in cloth, he fell into making lenses. He had no university training and no Latin, and wrote only in Dutch all his life.
Why this question
Hooke's microscope stacked several lenses. Leeuwenhoek's was different — a plain device holding a single tiny bead of glass, ground with extraordinary care.
It magnified over two hundred times, seeing far more than any instrument of the day. He never disclosed how he made the lenses.
What was found
He looked into a drop of rainwater and something was swimming there. Not one thing — a crowd. He called them little animals.
Then he scraped inside his own mouth. They were there too. He wrote that more of them live between one man's teeth than there are people in a kingdom.
He saw sperm, red blood cells, the fibers of muscle. He reported it all by letter to the Royal Society, and at first nobody believed him. In the end the Society sent men to Delft to look for themselves.
There were no living things below the reach of the eye
Swimming things found in rainwater, pepper water, and his own mouth
Connecting these small things to disease would take another two hundred years