ABOUT SCIENCE

Cell Theory | Theory of Cell | The Cell. About Cell Theory - Cell theory, the idea that the cell is the basic unit of life, was several centuries in the making

In 1665, Robert Hooke, an English scientist, coined the term cell and published the first  description of cells in his book Micrographia.

Hooke examined a piece of cork under a micro scope and saw a series of small boxlike chambers. He called these chambers “cells” because they reminded him of monks’ cells. We now know that what Hooke saw were not actually living cells but the cell walls that remain in dried plant tissue. 

In the late 1600s, the Dutch naturalist Antovan Leeuwenhoek became the first person to describe many types of living cells, including bacteria, sperm cells, and blood cells. After examining plaque scraped from his teeth under a microscope, van Leeuwenhoek wrote, in a 1683 letter to the Royal Society of London, about the amazing “animalcules” he saw: “I then most always saw, with great wonder, that in the said matter there were many very little living animalcules, very prettily a-moving. The biggest sort . .had a very strong and swift motion, and shot through the water (or spittle) like a pike does through the water. The second sort . . .

oft-times spun round like a top.”*

We now know that these animalcules were actually bacteria. It was not until the 1800s that the central importance of the cell was established. In 1838, careful studies of plants led German scientist Matthias Schleiden to conclude that all plants were made of cells. The following year, another German sci-

entist, Theodor Schwann, came to the same conclusion about animals.

The cell theory was finally completed in 1855 with German scientist Rudolph Virchow’s observation that all living cells come from other living cells. In summary, the cell theory states:

1. All living things are made up of one or more cells.

2. All cells come from other cells.