in Dental Plaque! (Ewwww!) – 1683
Until the late 1600s, nobody knew that there were tiny, invisible creatures living among (and in!) us. But on this date in 1683, Antony Van Leeuwenhoek wrote a letter to Britain's Royal Society describing tiny one-celled creatures he discovered while looking through a microscope.
He called these creatures “animalcules,” but today we call them bacteria.
Microscopes had been invented almost a century earlier, and even compound microscopes (those that combine ocular and objective lenses) had been created by Van Leeuwenhoek's time. However, the early compound microscopes were not able to get clear images at more than twenty or thirty times magnification. Van Leeuwenhoek was able to look at much smaller things using the simple microscopes he himself made—the best in the world, for the time—achieving magnifications above 200 times!
And what did he study using his powerful microscope? Plaque scraped from his own teeth and from the teeth of four other people.
Van Leeuwenhoek was surprised to see living creatures “very prettily a-moving.” Some shot through the plaque-and-water mixture, straight and swift, and others “spun round like a top.”
Van Leeuwenhoek later discovered foraminifera fossils, blood cells, animal sperm cells, and vacuoles in cells. (These are like storage bins inside cells. They contain water and important molecules.)
With all of this discovery, you are probably not surprised that Van Leeuwenhoek is considered the “Father of Microbiology.”
Biology4Kids has a website about microorganisms.
To learn about other founders of microbiology, check out this and this other earlier posts. (Both posts include other topics not related to microbiology. Just scan down to the picture of the microscope!) There are also activities such as a fun virtual microscope.