-
The microscope was built by Zacharias Janssen, probably with the help of his father Hans.
-
-
Robert Hooke's investigated the colours of membranes and of thin plates of mica, and established the variation of the light pattern with the thickness of the plates.
-
Anton Van Leeuwenhoek was the first to see and describe bacteria (1674),
-
He discovered the digestive enzyme pepsin.
-
Schleiden wanted to make cell formation analogous to crystal formation, and published his results in Beiträge zur Phytogenesis.
-
In 1839, he extended Schleiden's cell theory to animals, stating that all living things are composed of cells.
-
He summarized the cell theory with the Latin phrase "omnis cellula a cellula" (all cells arise from cells).