T e a c h e r  C r e a t e d  L e s s o n

Microorganisms in the 21st Century (part 1)


CHIN, Gatineau, Quebec

Early Research with the Microscope

Italian scientist Marcello Malpighi was one of the first great microscopists, and today is considered the father of embryology and histology. In 1661, Malpighi used a microscope to identify and describe the tiny blood vessels called capillaries, which link arteries to veins. This provided important support for William Harvey’s theory that the blood circulated from the heart to the extremities of the body and back again.

Antoni van Leeuwenhoek, with his simple, single lens microscope was capable of magnifying specimens from fifty to over two hundred times. The specimen was impaled on a pin, behind the lens, and the whole apparatus was held vertically to the eye.

Leeuwenhoek made remarkable observations with his very simple instrument, reporting his discoveries in letters to the Royal Society of London. In 1673, Leeuwenhoek described what were later recognized as blood corpuscles (red blood cells). His reports caused a sensation: he described ""animalcules,"" small moving creatures that appeared to be present in everyday matter!

In the 19th century the microscope allowed for observations of bacteria, and greatly facilitated the development of the germ theory of disease. This was the dawn of medical bacteriology, and the identification of specific bacteria responsible for many communicable diseases. In 1882, Robert Koch discovered a staining technique that enabled him to see Mycobacterium tuberculosis. What excited the world was not so much the scientific brilliance of Koch’s discovery, but the certainty that now the fight against one of humanity’s deadliest enemies could really begin.

The microscope has aided many Canadian scientific discoveries. This is the microscope from Dr. James Collip’s laboratory at McGill University. Between 1927 and 1947, Collip, a renowned Canadian biochemist, worked with Hans Selye at McGill, undertaking a wide-range of histological and biochemical studies of the endocrine glands.
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© CHIN 2001