
The disease is transmitted by contact , from man to man , was known since biblical times.
•Varo and Columella (First century B.C.) postulated that diseases were caused by invisible organisms which they called ‘Animalia minuta’.
•Fracastoriaus of Verona (1546) proposed a contagium vivum (living germs) as a possible cause of infectious disease.
•Von Plenciz (1762) suggested that each disease was caused by a separate agent.

Antonie Philips van Leeuwenhoek (1632 – 1723) :
He was the first scientist who observed bacteria and other microorganisms, using a single lens microscope constructed by him and he named those small organisms as ‘ Little animalcules’.
- Microscopic observation by van Leeuwenhoek.
- Published in Acta Eruditorum in 1682.
- He was also the first to document microscopic observations of muscle fibers, bacteria, spermatozoa, red blood cells and among the first to see blood flow in capillaries.

ROBERT HOOKE
•In 1678 he developed compound microscope and
confirmed Leeuwenhoek’s observations.
•Coined the term “Cell”.
SCIENTIFIC DEVELOPMENT OF MICROBIOLOGY

Louis Pastuer (1822-1895)
•He is known as Father of Microbiology. •His studies on fermentation led him to take interest in microbiology . He established that fermentation was caused by microbial agents.
Important contributions in microbiology : •Development of methods and techniques of bacteriology.
•He introduced the sterilization techniques and developed stream sterilizer, hot air oven and autoclave.
•He proves that all forms of life , even microbes, arose only from their like and not de-novo.
•He disproved the theory of spontaneous generation of disease and postulated the germ theory of disease.
•Studies on anthrax, chicken cholera and hydrophobia.
•He introduced attenuated live vaccines for prophylactic use.
•He had proposed the Principles of fermentation.
•He described the method of pasteurization of milk.
•He gives liquid media concept.
Swan neck flask experiment by Pasteur


Robert Koch (1843-1910)
•He is known as Father of Bacteriology.
•He was a German general practitioner.
•He introduced methods for isolation of pure strains of bacteria.
•He introduced solid media for the culture of bacteria.
•He also introduced staining techniques.
•He described hanging drop method for testing motility.
Discovered the anthrax bacillus (1876) ,
tubercle bacillus (1882) and the chlolera vibrios(1883).
KOCH’S POSTULATES
According to this a microorganism can be accepted as the causative agent of an infectious disease only if the following conditions are fulfilled.
1.The microorganism must be found in abundance in all organisms suffering from the disease, but should not be found in healthy organisms
2.The microorganism must be isolated from a diseased organism and grown in pure culture.
3.The cultured microorganism should cause disease when introduced into a healthy organism. The microorganism must be reisolated from the inoculated, diseased experimental host and identified as being identical to the original specific causative agent
KOCH’S PHENOMENON
1.Infection immunity; living tubercle bacilli, Mycobacterium tuberculosis, do not cause reinfection when inoculated into tuberculous guinea pigs. The animals are immune to reinfection even though their original infection continues to develop and eventually cause their deaths.
2.Rise of temperature and increase of the local lesion in a tuberculous subject following an injection of tuberculin.

Joseph Lister (1827-1912)
•He is known as Father of antiseptic surgery.
•He applied Pasteur work and introduced antiseptic techniques in surgery.
•His antiseptic surgeries involved the use of carbonic acid.

Paul Ehrlich (1854-1915)
•He is known as Father of chemotherapy.
His contributions :-
1.Applied stains to cell and tissue for study of their function.
2.Reported the acid fast nature of tubercle bacillus.
3.Proposed ‘Side chain theory’ of antibody production.
4.Discovered salvarsan sometimes called the magic bullet.
5.Introduced methods of standardising toxin and anti-toxin.
Later on he discovered neosalvarsan and created a new branch of medicine known as chemotherapy.
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