Anton van Leeuwenhoek

Anton van Leeuwenhoek was born in the town of Delft, Holland, in 1632. He had a rather unusual background for a scientist, beginning in the cloth trade in Amsterdam, and then becoming City Chamberlain of his native town. He became interested in the making of microscopes, however, and used them enthusiastically in his studies almost until his death in 1723.

The Microscopes

Leeuwenhoek’s microscopes were not at all like those seen in present-day laboratories. They had only one small lens, almost spherical, mounted between metal plates. Such a lens, although difficult to produce, gave considerable better magnification than any other microscope of the time. Leeuwenhoek did not invent the microscope (Galileo, often credited with the invention, is known to have used one some fifty years previously). His achievement lay rather in his skill in setting and grinding the lens more accurately than had been possible before.

Blood and the Circulation

One well-known study by the Dutch scientist was concerned with the circulation of the blood. William Harvey had made the great discovery of the circulation about 1616, but there remained the problem of how blood from the arteries was actually transferred to the veins to be returned to the heart. Leeuwenhoek’s work, together with that of another microscopist, Marcello Malpighi, showed that it passed through tiny tubes we now know as capillaries. In other studies Leeuwenhoek examined the structure of the skin, hair, teeth and the eye, observed minute creatures (now called Protozoa) in pond water, identified the eggs and pupae of ants and considered a host of other biological subjects.

Observation of Bacteria

Leeuwenhoek’s greatest success came, however, when he examined the tartar from hi own teeth. To his great surprise he saw that there were in the tartar ‘a large number of “little beasties” moving about in a highly amusing way’. The largest of them, he noted, ‘showed the liveliest and most active motion, passing through the saliva as a fish of prey darts through the sea’. This was almost certainly the first observation of the tiny plants called bacteria which are so important in our lives as agents of decay and disease.

This Dutch scientist was by no means the only pioneer in the use of the microscope. Robert Hooke, Nehemiah Grew, Marcello Malpighi and Jan Swammerdam were amongst the most famous early workers, opening a vast new field of research into the world of creatures too tiny to see with the naked eye.