Cell Theory Timline

Aristotle

335 BCE

Aristotle created methods on how to learn, reason and provided a theory on how embryos form and develop. This led to the rejection of spontaneous generation because embryos were later concluded as cells which are formed for other cells, which are formed from one sinlge cell.

Zacharias Janssen

1595

Zacharias along with his father Hans, were the inventors of the compound optical microscope. This invention made it easier and more practical to study white blood cells The idea of spontaneous generation was rejected because of their invention.

Jan Baptist van Helmont

1643

Jan realized that plants didn't get their food from soil. His invention led to the rejection of spontaneous generation. He put a willow tree in a pot containing dry soil. For the next 5 years he only added rain or distilled water to the pot. After the 5 years, he discovered that the willow had gained weight, but the soil lost weight. From this, he concluded that the tree had risen from water only.

Robert Hooke

1665

Hooke observed the first cell on a cork using a compound telescope. This led to the rejection of spontaneous generation because cells make up living organisms, so they couldn't come from thin air.

Anton van Leeuwenhoek

1670

Anton used the microscope to observe cells, and discovered bacteria and protozoa floating in cells. His discovery led to the rejection of spontaneous generation because it proved that bacteria comes from pre-existing cells, which can't come from spontaneous generation.

Lorenz Oken

1805

Oken stated that all living things come from and consist of cells. This led to the rejection of spontaneous generation because cells made up organisms, so spontaneous generation couldn't have made them.

Robert Brown

1833

Robert was responsible for the discovery of the nucleus of the cell. This led to the rejection of spontaneous generation because the nucleus in located in the cell, which was formed by pre-existing cells, which proves that objects don't come from thin air.

Matthias Schleiden

1838

Matthias concluded that all plants are made up of cells and an embryonic plant came from a single cell. This led to the rejection of spontaneous generation because it stated that plants didn't form out of thin air, they came from a single cell.

Theodor Schwann

1839

Theodor proposed the idea that cells were the basic assembly of animal structure. This invention helped lead to the rejection of spontaneous generation. He took nutrients and stylized it, and put the air on a high temperature. The result was, no microbes grew and no biological or chemical activity were observed in the broth either. This experiment convinced Schwann that he had killed all the microbes and no more could be produced, so the theory of spontaneous generation was incorrect.

Albrecht von Roelliker

1840

Albrecht discovered that sperm and eggs are also cells. This led rejection of spontaneous generation because cells come from pre-existing cells, so they can't come from thin air.

Rudolf Virchow

1855

Rudolf stated that all cells come from pre-existing cells. This led to the rejection of spontaneous generation because it proved that cells come from other cells, not out of thin air.

Louis Pasteur

1863

Louis invented pasteurization. This was done by heating wine to 50-60 degrees Celsius. He also figured out how to control beer fermentation. His discoveries led to the rejection of spontaneous generation because he put broth in a "swan neck" flask and sterilized it by boiling it. He broke the neck of the flask after boiling it and the broth became cloudy. This meant that it was carbonated. He conducted the same experiment, but he didn't break off the neck of the flask and it remained sterile.