Microbiology began when people learned to grind lenses from pieces of glass and combine them to produce magnifications great enough to enable microbes to be seen.

Roger Bacon (1220-1292) postulated that disease is produced by invisible living creatures.

Girolamo Fracastoro of Verona (1483-1553) and Anton von Plenciz in 1762 suggested that disease is produced by invisible living creatures.

Athanasius Kircher (1601-1680) was the first person to recognize the significance of bacteria and other microbes in disease.

In 1665, Robert Hooke's description of cells in a piece of cork established that the bodies of 'animals and plants, complex as they may appear, are yet composed of a few elementary parts frequently repeated'.

Antony van Leeuwenhoek (1632-1723) was the first to report his observations of bacteria and protozoa with accurate descriptions and drawings.

The most powerful microscopes made by Antony van Leeuwenhoek would magnify about 200 to 300 times.

A modern compound light microscope is capable of magnifications of 1,000 to 3,000 times.

Antony van Leeuwenhoek carefully recorded his observations in a series of letters to the British Royal Society, addressed to Henry Oldenburg, Secretary of the Royal Society.

In a letter dated September 7, 1674, Leeuwenhoek described the 'very little animalcules' which we recognize as free-living protozoa.

In 1675, Leeuwenhoek discovered living creatures in rainwater that had stood for a few days in a new, glazed earthen pot.

On June 16, 1875, Leeuwenhoek reported discovering incredibly many very little animalcules of divers sorts and sizes in a tiny drop of well water.

Before the time of Pasteur, microorganisms were studied mainly to satisfy curiosity concerning their characteristics and their relationships to higher living forms, without awareness of their importance in fermentation and disease.

Aristotle (384-322 B.C.) taught that animals might originate spontaneously from the soil, plants, or other unlike animals.

It was accepted as a fact that maggots could be produced by exposing meat to warmth and air.

Francesco Redi placed meat in a jar covered with gauze. Flies laid eggs on the covering, and maggots developed from the eggs, proving they originated from flies, not the meat.

In 1749, while experimenting with meat exposed to hot ashes, John Needham observed the appearance of organisms not present at the start of the experiment and concluded that the bacteria originated from the meat.

Lazaro Spallanzani boiled beef broth for an hour and then sealed the flask. No microbes appeared following incubation.

Franz Schulze passed air through strong acid solutions into boiled infusions, and Theodor Schwann passed air into his flasks through red-hot tubes. In neither case did microbes appear.

H. SchrOder and T. von Dosch passed air through cotton into flasks containing heated broth. The microbes were filtered out by the cotton fibers, preventing growth.

Felix-Archimede Pouchet published an extensive report in 1859 'proving' the occurrence of spontaneous generation.

Pasteur prepared a flask with a long, narrow gooseneck opening. Nutrient solutions were heated in the flask, allowing air to pass in or out, but airborne germs settled in the gooseneck, preventing microbial growth in the solution.

John Tyndall conducted experiments in a specially designed box to prove that dust carried the germs. He demonstrated that if no dust was present, sterile broth remained free of microbial growth for indefinite periods.

Louis Pasteur began his career as a professor of chemistry at the University of Lille, France, studying the manufacture of wines and beer.

Pasteur found that fermentation of fruits and grains, resulting in alcohol, was brought about by microbes. He observed that different types of microbes predominated in good and poor batches of ferment.

Pasteur found that holding juices at a temperature of 62.8°C (145°F) for half an hour was effective for pasteurization.