English physicist Robert Hooke first described cells in 1665

English physicist Robert Hooke first described cells in
1665. He made thin slices of cork (a type of tree) and
observed many small boxes that reminded him of cells
(small rooms) in a monastery. So, he called what he saw
under the microscope “cells”. Because the cork was already
dead and dried, the cells were empty. At the time Hooke
thought they had only contained water when the cork was
alive.
In 1670, Antony van Leeuwenhoek, built a simple microscope that would magnify at 250x. He
was the first person to observe bacteria and protozoa. He studied Protists, plant cells, various
types of algae, and was the first person to view bacteria, which he termed “animalcules”.
Leeuwenhoek discovered these bacteria while viewing scrapings from his teeth and the teeth of
others. He also discovered blood cells and was the first to see living sperm cells in animals.