HISTORY OF MICROBIOLOGY
The history of microbiology is divided in to 4 eras
THE DISCOVERY ERA:-
Before
17th century study of microbiology was hampered by the lack of
appropriate tools to observe microbes. The microbial world was unknown until
the invention of microscopes, because micro-organisms are too small to be seen
clearly by the naked eyes.
The
principle of telescope and microscope was accidentally discovered by Zacharias
jansen in 1609.
ROBERT HOOKE (1635-1703): English
scientist, was the first to use a simple lens to observe the smallest unit of
tissues he called “cells”. He examined the slices of cork from the bark of an
oak tree. He observed that cork was made of tiny boxes that he referred to as
cells.
ANTOINE VAN LEEUWENHOEK (1632-1723): He was the first to observe & describe the
shape of human red blood cells as well as the little agent of disease.
He was the first person to observe and accurately
describe live microorganisms (bacteria and protozoa) called ‘animalcules’
(little animals) in 1676. He took scurf from the root of decayed tooth &
mixed it with clean rain water & saw the mobility in animals.
Actually he was a Dutch linen merchant but
spent much of his spare time constructing simple microscopes composed of double
convex lenses held between two silver plates. He constructed over 250 small
powerful microscopes that could magnify around 50-300 times.
Leeuwenhoek
was the first person to produce precise and correct descriptions of bacteria
and protozoa using a microscope he made himself. Because of this extraordinary
contribution to microbiology, he is considered as the “Father of microbiology”
and also considered to be the father of bacteriology and protozoology.
TRANSITION ERA:-
SPONTANEOUS GENERATION V/S BIO-GENESIS:-
When microorganisms were known to exist, most
scientists believed that such simple life forms could surely arise through
spontaneous generation. i.e. That living organism could arise from non
living matter (mud and lakes or anywhere with sufficient nutrients).
E.g.
Maggots comes from rotting meat
Ants comes from honey
Microbes comes from spoiled broth.
[Theory of bio-genesis:-
Belief that living cells can only arise from other living cells.]
The main aspects were to solve the controversy
over spontaneous generation which includes experimentations mainly of Francesco Redi, John Needham, Lazzaro Spallanzani.
FRANCESCO REDI (1626-1697): The
ancient belief in spontaneous generation was first of all challenged by Redi,
an Italian physician, who carried out a series of experiments on decaying meat
and its ability to produce maggots spontaneously. He showed that maggots would
not arise from decaying meat, when it is covered.
JOHN NEEDHAM (1713-1781): He
was probably the greatest supporter of the theory of spontaneous generation. He
proposed that tiny organisms the animalcules arose spontaneously on his mutton
gravy. He covered the flasks with cork as done by Redi and even heated some
flasks. Still the microbes appeared on mutton broth.
LAZZARO SPALLAZANI
(1729-1799): Lazzaro Spallazani, an Italian priest - boiled beef broth for an
hour, sealed the flasks and observed no appearance of microorganisms and
disproved the theory of spontaneous generation and proposed the theory of
biogenesis.
He
said that every form of life takes its origin from their parents, germ
cells or seeds. This theory of bio-genesis was later proved and supported by
Louis Pasteur.
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