-
convex lenses with a magnification greater than x5 became available
-
First compound microscopes used in Europe (used 2 convex lenses to make objects look larger). Suffered badly from colour distortion- an effect called 'spherical aberration'
-
Antoni van Leeuwenhoek of Leyden, Holland, produced over 500 single lens microscopes. Discovered bacteria, human blood cells, spermatozoa, and protozoa.
-
He used lenses to study insects, discovered capillaries and may have described cells in writing of 'globules' and 'saccules'
-
He introduced the term 'cell' in describing the microscopic structure of cork and he believed that the cell walls were the important part of the otherwise empty structures.
-
Wrote the first of two well-illustrated books on the microscopic anatomy of plants
-
They proposed the cell theory for plants and animals: that plants and animals are composed of groups of cells and that the cell is the basic unit of living organisms
-
Extended the cell theory by stating that: new cells are formed only by the division of previously existing cells
-
Added to Virchow's idea by pointing out that: all the cells living today can trace their ancestry back to ancient times (cell theory -> evolution)