Antonie Leeuwenhoek
1686
Antony van Leeuwenhoek, as painted by Johannes Verkolje. On the table is the Royal Society Letter of Fellowship.
Antonie Leeuwenhoek
Antonie van Leeuwenhoek looking through one of his tiny single-lens microscopes and recording his observations. The sample he is viewing is held within the body of the microscope.
Antonie Leeuwenhoek
1686
Antony van Leeuwenhoek, as painted by Johannes Verkolje. On the table is the Royal Society Letter of Fellowship.
1926
Delft, The Netherlands
Van Leeuwenhoek's birth house, before it was demolished.
Antonie van Leeuwenhoek looking through one of his tiny single-lens microscopes and recording his observations. The sample he is viewing is held within the body of the microscope.
A cross-sectional view of a nerve fiber drawn by Antonie van Leeuwenhoek.
One of Leeuwenhoek’s drawings of red blood cells.
Antonie Leeuwenhoek
Leeuwenhoek’s letters to the Royal Society Courtesy of the Delft University Library.
One of Antoni van Leeuwenhoek’s microscopes.
Packets of dried algal “paper” specimens that Leeuwenhoek sent to London.
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Businessman inventor microbiologist microscopist naturalist scientist
Antonie van Leeuwenhoek was born in Delft, Dutch Republic, on 24 October 1632. His father, Philips Antonisz van Leeuwenhoek, was a basket maker who died when Antonie was only five years old. His mother, Margaretha (Bel van den Berch), came from a well-to-do brewer's family. She remarried Jacob Jansz Molijn, a painter. Antonie had four older sisters, Margriet, Geertruyt, Neeltje, and Catharina. When he was around ten years old his step-father died.
Antonie van Leeuwenhoek attended school in Warmond for a short time before being sent to live in Benthuizen with his uncle, an attorney. At the age of 16 he became a bookkeeper's apprentice at a linen-draper's shop in Amsterdam, which was owned by William Davidson. Van Leeuwenhoek left there after six years.
Returning to Delft when he was 20, Antonie van Leeuwenhoek established himself as a draper and haberdasher. In 1660 Leeuwenhoek obtained a position as chamberlain to the sheriffs of Delft. His income was thus secure, and it was thereafter that he began to devote much of his time to his hobby of grinding lenses and using them to study tiny objects.
Leeuwenhoek made microscopes consisting of a single high-quality lens of very short focal length; at the time, such simple microscopes were preferable to the compound microscope, which increased the problem of chromatic aberration. Although Leeuwenhoek’s studies lacked the organization of formal scientific research, his powers of careful observation enabled him to make discoveries of fundamental importance. In 1674 he likely observed protozoa for the first time and several years later bacteria. Those “very little animalcules” he was able to isolate from different sources, such as rainwater, pond, and well water, and the human mouth and intestine. He also calculated their sizes.
In 1677 he described for the first time the spermatozoa from insects, dogs, and man, though Stephen Hamm probably was a co-discoverer. Leeuwenhoek studied the structure of the optic lens, striations in muscles, the mouthparts of insects, and the fine structure of plants and discovered parthenogenesis in aphids. In 1680 he noticed that yeasts consist of minute globular particles. He extended Marcello Malpighi’s demonstration in 1660 of the blood capillaries by giving the first accurate description of red blood cells.
A friend of Leeuwenhoek put him in touch with the Royal Society of England, to which he communicated by means of informal letters from 1673 until 1723 most of his discoveries and to which he was elected a fellow in 1680. His discoveries were, for the most part, made public in the society’s Philosophical Transactions. The first representation of bacteria is to be found in a drawing by Leeuwenhoek in that publication in 1683.
His researches on the life histories of various low forms of animal life were in opposition to the doctrine that they could be produced spontaneously or bred from corruption. Thus, he showed that the weevils of granaries (in his time commonly supposed to be bred from wheat as well as in it) are really grubs hatched from eggs deposited by winged insects. His letter on the flea, in which he not only described its structure but traced out the whole history of its metamorphosis, is of great interest, not so much for the exactness of his observations as for an illustration of his opposition to the spontaneous generation of many lower organisms, such as “this minute and despised creature.” Some theorists asserted that the flea was produced from sand, others from dust or the like, but Leeuwenhoek proved that it bred in the regular way of winged insects.
Leeuwenhoek carefully studied the history of the ant and was the first to show that what had been commonly reputed to be ants’ eggs were really their pupae, containing the perfect insect nearly ready for the emergence and that the true eggs were much smaller and gave origin to maggots, or larvae. He argued that the sea mussel and other shellfish were not generated out of sand found at the seashore or mud in the beds of rivers at low water but from spawn, by the regular course of a generation. He maintained the same to be true of the freshwater mussel, whose embryos he examined so carefully that he was able to observe how they were consumed by “animalcules,” many of which, according to his description, must have included ciliates in conjugation, flagellates, and the Vorticella. Similarly, he investigated the generation of eels, which were at that time supposed to be produced from dew without the ordinary process of generation. The dramatic nature of his discoveries made him famous, and he was visited by many notables - including Peter I (the Great) of Russia, James II of England, and Frederick II (the Great) of Prussia.
Leeuwenhoek’s methods of microscopy, which he kept secret, remain something of a mystery. During his lifetime he ground more than 500 lenses, most of which were very small - some no larger than a pinhead - and usually mounted them between two thin brass plates, riveted together. A large sample of those lenses, bequeathed to the Royal Society, were found to have magnifying powers in the range of 50 to, at the most, 300 times. In order to observe phenomena as small as bacteria, Leeuwenhoek must have employed some form of oblique illumination, or other technique, for enhancing the effectiveness of the lens, but this method he would not reveal. Leeuwenhoek continued his work almost to the end of his long life of 90 years.
Anton van Leeuwenhoek is widely known as "the Father of Microbiology", and often considered to be the first acknowledged microscopist and microbiologist. He studied a broad range of microscopic phenomena, and shared the resulting observations freely with groups such as the British Royal Society. Van Leeuwenhoek's main discoveries are: infusoria, bacteria, the vacuole of the cell, spermatozoa and the banded pattern of muscular fibers.
In 1674, aged 41, Leeuwenhoek made the first of his great discoveries: single-celled life forms. Nowadays these organisms are grouped with the protists – these are mainly single-celled plants and animals. Echoing the initial disbelief Hooke’s Micrographia had met, many members of the Royal Society refused to believe in the existence of Leeuwenhoek’s microscopic creatures. It took until 1677 before their existence was fully accepted. This happened after Robert Hooke returned to his microscopes, which he had given up because of eye strain, and verified Leeuwenhoek’s observations.
In 1674 Leeuwenhoek examined red blood cells, which had been discovered six years earlier by his fellow Dutchman, Jan Swammerdam. With his superior lens, Leeuwenhoek was able to give a clearer description of the cells than ever before and was the first person to determine their size accurately.
In 1676 Leeuwenhoek discovered bacteria in water. The bacteria were at the limit of observation of his microscope - he estimated that it would take more than 10,000 of them to fill the volume of a small grain of sand. Such was the brilliance of his work that nobody else observed bacteria until another century had passed.
In 1677 Leeuwenhoek discovered spermatozoa, later concluding that eggs are fertilized when entered by sperm.
In 1683 Leeuwenhoek discovered the lymphatic capillaries, which contained “a white fluid, like milk.”
By observing the life-cycles of maggots and fleas Leeuwenhoek proved that such creatures are not spontaneously generated, as many people believed at the time. He showed these creatures go through a process of reproduction from eggs to maggots to pupae to adults.
By dissecting aphids he discovered parthenogenesis. He found parent aphids containing the embryos of new aphids although eggs had not been fertilized. By observing the flow of blood in tiny capillaries, Leeuwenhoek confirmed William Harvey’s work on blood circulation.
Quotations:
"My work, which I've done for a long time, was not pursued in order to gain the praise I now enjoy, but chiefly from a craving after knowledge, which I notice resides in me more than in most other men. And therewithal, whenever I found out anything remarkable, I have thought it my duty to put down my discovery on paper, so that all ingenious people might be informed thereof."
"I observed certain animalcules, within whole bodies I saw so quick a motion as to exceed belief; they were about the size of a large grain of sand, and their bodies being transparent, that the internal motion could plainly be seen. Among other things, I saw in the body of one of these animalcules a bright and round corpuscle, placed near the head, and in which a very wonderful swift motion was to be seen, consisting of an alternate extension and contraction. This article I concluded to be the heart…”
Antonie van Leeuwenhoek was elected to the Royal Society in February 1680 on the nomination of William Croone, a then-prominent physician. Van Leeuwenhoek was "taken aback" by the nomination, which he considered a high honor, although he did not attend the induction ceremony in London, nor did he ever attend a Royal Society meeting.
Royal Society , United Kingdom
1680
Physical Characteristics: Van Leeuwenhoek suffered from Respiratory Myoclonus, a rare disease, and uncontrolled movement of the midriff, which now is named van Leeuwenhoek's disease.
Quotes from others about the person
"It was a standing joke of [Dr. Chapman] to quote old Leuwenhoeck as having discovered 'twenty thousand devils playing upon the point of a needle' thus foreshadowing some of the most remarkable discoveries of the present day, especially disease germs." - John Light Atlee.
"Among those whom I could never persuade to rank themselves with idlers, and who speak with indignation of my morning sleeps and nocturnal rambles, one passes the day in catching spiders, that he may count their eyes with a microscope; another exhibits the dust of a marigold separated from the flower with a dexterity worthy of Leuwenhoweck himself. Some turn the wheel of electricity; some suspend rings to a lodestone, and find that what they did yesterday, they can do again today. - Some register the changes of the wind, and die fully convinced that the wind is changeable. - There are men yet more profound, who have heard that two colorless liquors may produce a color by union, and that two cold bodies will grow hot of they are mingled: they mingle them, and produce the effect expected, say it is strange, and mingle them again." - Samuel Johnson
Van Leeuwenhoek married Barbara de Mey in July 1654, with whom he fathered one surviving daughter, Maria (four other children died in infancy). His wife died in 1666, and in 1671, Van Leeuwenhoek remarried to Cornelia Swalmius with whom he had no children.
