Hans and Zacharias Janssen

• Dutch lens grinders; father and son
  
• produced first compound microscope (2 lenses)

• English scientist
  
• looked at a thin slice of cork (cork oak) through a compound microscope
  
• observed tiny, hollow, roomlike structures
  
• called these structures 'cells' because they reminded him of the rooms that monks lived in
  
• only saw the outer walls (cell walls) because cork cells are not alive

• Dutch fabric merchant and amateur scientist
  
• looked at blood, rainwater, scrapings from teeth through a simple microscope (1 lens)
  
• observed living cells; called some 'animalcules'
  
• some of these small 'animalcules' are now called bacteria

• German botanist
  
• viewed plant parts under a microscope
  
• discovered that plant parts are made of cells

• German zoologist
  
• viewed animal parts under a microscope
  
• discovered that animal parts are made of cells

• German physician
  
• stated that all living cells come only from other living cells