Louis pasteur and Koch collectively came up with the conclusion that a particular microorganism causes a disease. They called this the germ theory.
However, what does spontanous generation say about how disease is inherited/come about? All the textbook states is that micro-organisms do not arise spontaously.
Louis Pasteur’s swan-neck experiment, his conclusions and issues regarding validity
Louis Pasteur’s swan-neck experiment was purposed to scientifically disprove the theory of spontaneous generation – that diseases arise spontaneously, and do not have an instigator.
• Pasteur’s Swan-neck Experiment:
He sought to disprove the theory of spontaneous generation
He hypothesised that microbes were in the air everywhere, and food spoils when these microbes land there and become active
Pasteur poured nutrient broth into 2 identical swan-necked flasks, and boiled both of them to kill off all microbes
Then he broke one of the ‘necks’ and left both flasks out in the open air
As he predicted, the flask with the broth open to the air developed cloudy bacterial growths, while the flask with the swan-neck stayed clear
He demonstrated that only when sterilised broth was exposed to air in the straight-necked flasks did changes in the broth occur
This proved that the microbes (micro-organisms) that spoil food come from the air, and land in specific foods, initiating microbial growth and transmitting diseases
Cells come from pre-existing cells, not arise spontaneously. This is a great contribution because previous scientific thought was centralized on spontaneous generation. Microbes are constantly in the air, they must land in the broth first as they did with the straight-necked flask, and feed off the broth, replicating and creating a microbial infection within the broth. Once they are in there, the bacteria will replicate because broth is food, so they can feed off this. It Is the perfect conditions to replicate
This fundamentally disproved spontaneous generation, which states that diseases arise spontaneously – if this was the case, they would have come into existence from within the broth spontaneously, not sourced from the air.
To validate this scientific principle, the swan-necked flask remains clear of any microbial infection, because the microbes, being pathogens, were trapped in the s-bend of the flask, unable to enter the broth like the straight-necked flask
Louis Pasteur’s experimental flask remains in the Paris Museum, still bacteria free, over a century later
Pasteur concluded that microbes from the air were able to infect the broth in the straight-necked flasks, because it gave way to the microbes that are travelling in the air to fall into these broths, while the swan-necked flasks exhibited a design that inhibited the microbes to enter into the broth, being trapped into the S-bend (loop) of the flask
HOWEVER, the issue with regards to VALIDITY is that his findings i.e. Louis disproving spontaneous generation CANNOT be extrapolated to ancient Earth - meaning that spontaneous generation could have occurred on Ancient Earth when the chemical and physical composition of the environment was very different, and has evolved to what it is today. They are only valid in a contemporaneous scientific context.
Wow, I can't sleep so I'm doing this. LOL.
So tired due to lack of sleep in previous days.
