Louis Pasteur sterilized nutrient broth by boiling it in flasks whose necks were drawn out into a long, S-curved swan neck. The curve let air reach the broth but trapped airborne dust and microorganisms, so the broth stayed clear indefinitely unless the neck was broken. The result showed that microbial growth came from outside contamination, not spontaneous generation, and effectively ended that debate.
Facts
Year1859 is the year Britannica's account of Pasteur anchors his decision to settle the spontaneous-generation dispute and the swan-neck flask work that followed; some secondary sources place the most widely reproduced demonstrations as late as 1861 to 1862. MethodSourced to the subject's own accountPasteur boiled a fermentable broth in flasks with long curving swan necks that let air reach the liquid while trapping airborne dust and microbes in the curve, then compared these flasks to ones tilted so the broth touched the contaminated neck. 2 Key FindingSourced to the subject's own accountBroths in unswirled swan-neck flasks stayed sterile indefinitely, and only grew organisms once tilted to contact the dust-laden neck, showing the microbes came from outside on airborne dust rather than arising spontaneously in the broth. 2 Cross-Tradition Connections
Conducted By
Tests
Pasteur's 1859 to 1864 swan-neck flask experiments disproved spontaneous generation by showing sterilized broth stayed sterile so long as airborne microorganisms, not air itself, were kept from reaching it; this removed the leading rival explanation for microbial growth and cleared the ground for germ theory acceptance.
Sources
Reader Challenges (0 open reader challenges)
No disputes yet. Spotted an error or a better source? Open the first one.
Sign in to dispute this or suggest a correction.
View At A Past Year
The atlas records no dated fact of its own for this entry, so there is no other year to choose.