He made the first compound microscope! The microscope was a tube with lenses at the end.
He made a new microscope with improved lenses so he could see stuff like bacteria
Robert made a more complex microscope. it had a oil lamp for lighting, a lens that focuses the light from the flame
He stated that plants tissues were composed of cells
He said that all cells come from pre-exiting cells
He was one of the first to back up Robert Remak's theory that all cells come from pre-existing cells
He concluded that all plants are made up of cells