Microbiology: Microbiology History.

Earlier the term Microbiology was inconsistent as the theory of Spontaneous generation was predominant.

MICROBIOLOGY : is defined as the study of organisms and agents of the order less than 1 mm and which cannot be seen by the unaided eye.

Exceptions :

Among Eukaryotic : Bread mould and filamentous algae.

Among Prokaryotic : Bacteria such as Epulopiscium and Thiomargarita species.

Spontaneous Generation of Microbes :

From earliest times people believed that organisms develop from inanimate matter.

Aristotle said that some simpler invertebrates can arise by spontaneous generation.

He was challanged by Italian scientist Francesco Redi.

REDI's EXPERIMENT :

AIM : To prove that organisms arise from organisms and not from non-living matter.

Material and apparatus : 3 Jars, fine gauze, paper.

Method :

He placed meat in 3 jars .

One was covered with paper, other with gauze and the third was left open.

Observation :

Flies developed in the open jar.

Flies visited the jar with gauze and laid their eggs over it. Maggots again developed.

The third jar remained sterile even after the meat had decayed.

Conclusion :

Meat did not spontaneously generate maggots as previously believed.

Similar experiments by others on mice disproved the theory of Spontaneous generation.

Renewal of Spontaneous generation:

Leewenhoek's discovery of Micro-organisms renewed the theory of Spontaneous generation.

John Needham :

He was an English priest who supported the theory of spontaneous genration.

Needham's experiment:

He Boiled mutton broth in a flask and then tightly stoppered it.

Eventually the flasks became hazy and contained micro-organisms.

The Italian Scientist Lazarro Spallanzani opposed Needham by his experiment :

Spallanzani's experiment :

He first sealed the flasks containing water and seeds and then placed it in boiling water for 3/4 th of an hour.

No growth took place as long as the flasks were sealed.

Could not convince the supporters of spontaneous generation that heating the air in flasks destroyed its ability to support life.

Theodar schwann :

He allowed air to pass into sterile nutrient medium after it had passed through Red hot tube.

The flask remained sterile.

Schroder and Dusch:

They allowed air to enter into a sterile medium after it had been passed through sterile cotton.

No growth occured.

Despite these proofs French naturalist, Felix pouchet claimed to have carried out an experiment where microbial growth occured even without air contamination.

This provoked the anger of Louis Pasteur and he decided to finish off the theory of spontaneous generation forever.

ENTRY OF PASTEUR :

He placed nutrient solutions in a flask, heated their necks in a flame, and them out through a variety of curves, while keeping the end of necks open to atmosphere.

He then boiled the solutions for a few minutes and allowed them to cool.

No growth occured even after the contents were exposed to air.

Pasteur pointed that no growth occured because dust and germs had been trapped in the curved necks.

If curved necks were broken, growth commenced immediately.

This proof was readily accepted as Pasteur did not change the constitution of air nor did he heat it. He allowed normal air to pass into the nutrient media but only through the curved necks.