Who first used a swan-neck flask to disprove spontaneous generation?

• A. Robert Hooke
• B. Robert Koch
• C. Antonie van Leeuwenhoek
• D. Louis Pasteur

Answer: (D)

The main concept tested is how life arises and how scholars demonstrated that it comes from preexisting life, not from nonliving matter. Louis Pasteur showed this decisively with the swan-neck flask. He boiled nutrient broth to sterilize it, then left the curved-neck flask exposed to air. The bend in the neck allowed air to enter but trapped dust and microorganisms, so no microbes reached the broth and it stayed sterile. When the flask was later tipped so the liquid contact with trapped particles occurred, or when the neck was broken, microbes fell into the broth and growth began. This demonstrated that microorganisms come from the environment, not from spontaneous generation.

Robert Hooke contributed to early microscopy and coined the term cell, but he did not perform this experiment. Antonie van Leeuwenhoek first observed living microbes with his simple microscopes, again not the spontaneous-generation demonstration. Robert Koch later established postulates linking specific microbes to diseases, not the spontaneous-generation disproval.