• Reported that all living things are composed of 'little boxes' or cells
• laid the foundation for the development of the Cell theory
• all living things are composed of cells and come from preexisting cells
  

• first observed microorganisms using magnifying lenses (First microscope)

• disproved spontaneous generation (showed that microorganisms are present in the air)
• discovered Fermentation (microbes can conbert sugars to alcohol to make beer and wine)
• Pasteurization (use heat to prevent food spoilage)
• aseptic techniques

• used a chemical disinfectant to prevent surgical wound infections (aseptic principles of surgery)

Robert Koch

• proved that a bacterium causes anthrax and provided the experimental steps (koch's postulates) to prove that a specific microbe causes a specific disease (Germ theory of disease)

• Inoculated a person with cowpox virus who was then protected from small pox
• First vaccine

• developed the Theory of Immunity
• used a synthetic arsenic drug to treat Syphilis

James Watson

Francis Crick