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Rudolf Virchow challenged the theory of spontaneous generation.
He agreed with the concept of biogenesis (living organisms can only arise from preexisting life) but he couldn't provide any scientific proof. -
Joseph Lister uses chemical disinfectant
He used a chemical disinfectant to prevent surgical wound infections after seeing Louis Pasteur's work proving that microbes are in the air. Those microbes can spoil food and cause diseases. -
Louis Pasteur demonstrated that microorganisms are present in the air.
In his experiments he placed nutrient broth in a flask, heated it and didn't seal it which resulted in microbial growth. In another flask he also placed nutrient broth and heated it as well but this time he sealed the flask which resulted in no microbial growth. Proving that microorganisms are in the air and can contaminate sterile solutions. -
Louis Pasteur disproved spontaneous generation
He placed broth in long-neck flasks and bent the neck into S-shaped curve. He hypothesized that airborne microorganisms would settle at the base of the S-shaped neck and not contaminate the broth. He sterilized the broth and left the swan neck flask open. Even after several months, the broth in the flasks did not show contamination with microorganisms. Proving that microorganisms come about from the presence of microbes in the air or in the fluid itself. -
Louis Pasteur fermentation and pasteurization
He showed that microbes are responsible for fermentation (the conversion of sugar to alcohol) and that microbial growth is responsible for food spoiling. He showed that these bacteria that causes spoilage can be killed with heat/ pasteurization (the application of heat for a short amount of time). -
Louis Pasteur believed that another silkworm disease was caused by a protozoan.
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Robert Koch proved that a bacterium causes anthrax and gave the experimental steps.
He proved that bacterium causes anthrax. He also provided the experimental steps to prove that a specific microbe causes a specific disease. The steps are known as Koch's Postulates. -
Alexander Fleming discovers penicillin
He found that the growth of S. aureus was prevented by a molecule produced by mold, penicillin the first antibiotic discovered.
