NURSING ANM AND GNM

Detailed explanation-1: -(i) Swan-necked flask experiment was done by Louis Pasteur. (ii) The early belief of the spontaneous origin of life was disproved by Louis Pasteur.

Detailed explanation-2: -He concluded that with biogenesis the new living things can be created through reproduction. Hence, Louis Pasteur disproved the abiogenesis theory experimentally.

Detailed explanation-3: -He heated an infusion sealed in a vessel with a S-shaped or “Swan neck", let it cool, and then broke of the tip of the vessel. This allowed fresh air to enter, but any particulate matter was trapped in the bend of the neck. The culture did not putrefy, even though it had access to air.

Detailed explanation-4: -After prolonged incubation the swan necked flask remained free of life, whereas the control flask was teeming with microbial life. Thus, Pasteur succeeded in disproving the spontaneous generation theory because the swan neck of the flask allowed only air, and not the microbes.

Detailed explanation-5: -Disproving Spontaneous Generation In 1858, Pasteur filtered air through a gun-cotton filter and, upon microscopic examination of the cotton, found it full of microorganisms, suggesting that the exposure of a broth to air was not introducing a “life force” to the broth but rather airborne microorganisms.