Specimens: Ovaries

Leeuwenhoek observed ovaries in various animals for forty years. He was a spermist (also called animalculists), who theorized that reproduction occurred through the sperm. The role of the ovaries and eggs was not clear to them. The number of ovists, who theorized that reproduction occurred through the female egg, far out-numbered the spermists.

Links to letters below under Learn more.

1678 March 18 (Letter 38 [24]) to Nehemiah Grew: cows and lambs

1683 January 22 (Letter 70 [37]) to Christopher Wren: lambs

1685 March 30 (Letter 84 [45]) to Members of the Royal Society: theory of reproduction, sheep, dog, rabbit, calves, lambs

1687 August 6 (Letter 102 [57]) to Members of the Royal Society: calander

1687 October 17 (Letter 104 [59]) to Members of the Royal Society: blowfly

1692 March 7 (Letter 119 [71]) to Members of the Royal Society: corn moth

1693 October 15 (Letter 126 [76] to Members of the Royal Society: flea

1693 December 20 (Letter 129 [77]) to Members of the Royal Society: crane fly

1694 March 19 (Letter 135 [81]) to Members of the Royal Society: animalculist response to ovulist George Garden, referring to a variety of animals

1694 April 30 (Letter 137 [83]) to Members of the Royal Society: mussels, barnacle, other shell fish

1694 November 30 (Letter 140 [85] to Peter Rabus: dragon flies

1695 May 21 (Letter 145) to Peter Rabus: ray

1695 July 10 (Letter 147 [90]) to Frederik Adriaan van Reede van Renswoude: aphids)

1695 September 18 (Letter 157 [95]) to Johann Wilhelm von Pfalz-Neuburg: mussels and other shell fish, louse

1696 February 20 (Letter 164 [98] to Frederik Adriaan van Reede van Renswoude: louse

1700 June 2 (Letter 211 [125]) to Frederik Adriaan van Reede van Renswoude: shrimp

1701 December 6 (Letter 231 [142] to John Somers: hen

1704 March 21 (Letter 248) to Members of the Royal Society: cochineal

1716 May 19 (Letter 322 [XXIII]) to Gottfried Leibniz: dogs, rabbits, sheep

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Specimens: Sperm

Related letters:

What Leeuwenhoek wrote ...
Wrote Letter L-070 of 1678-03-18 to Nehemiah Grew about sperm in other animals and what Harvey and de Graaf got wrong about reproduction
Wrote Letter L-122 of 1683-01-22 to Christopher Wren about the function of the ovary, muscles of insects, drinking tea and mild beer, erythrocytes, and a theory on the formation of blood
Wrote Letter L-157 of 1685-03-30 to Members of the Royal Society about sperm, the uterus of a bitch, sheep embryos, ovaries in young animals and apples, and his claims that sperm are the life-carriers and that there are male and female sperm
Wrote Letter L-190 of 1687-08-06 to members of the Royal Society about the calander and the louse and against spontaneous generation
Wrote Letter L-193 of 1687-10-17 to members of the Royal Society about amber, 'burned paper' from the sky, rotifers, maggots, blow flies, the stinging hairs of nettles, and the East-Indian centipede
Wrote Letter L-216 of 1692-03-07 to the members of the Royal Society about corn-weevels, corn-moths, caterpillars, butterflies, calanders, lice in corn-lofts, little animals in rain water, black-flies in blossoms, and maggots in cheese
Wrote Letter L-228 of 1693-10-15 to the members of the Royal Society about colors and the life cycle of fleas
Wrote Letter L-231 of 1693-12-20 to the members of the Royal Society about spiders, lice, and mites
Wrote Letter L-240 of 1694-03-19 to the members of the Royal Society refuting George Garden's ideas in Letter L-227 about the role of the ovary and eggs
Wrote Letter L-242 of 1694-04-30 to the members of the Royal Society about his criticisms of Buonanni's theory of spontaneous generation, about mussels, barnacles, shrimp larvae, the eye of a dragon-fly, gnat, fly, and ant, and about ant eggs
Wrote Letter L-246 of 1694-11-30 to Pieter Rabus about about dragon-fly eyes and eggs, crab eyes, vertebrate corneas, another rejection of spontaneous generation, and the impregnation of women
Wrote Letter L-254 of 1695-05-21 to Pieter Rabus about the eggs and blood vessels of the ray
Wrote Letter L-260 of 1695-07-10 to Frederik Adriaan van Reede about aphids, their reproduction, and the unsuccessful search for male aphids
Wrote Letter L-271 of 1695-09-18 to Johann Wilhelm von Pfalz-Neuburg about swan mussel sperm, eggs, embryos, and locomotion, small animals as food for larger ones and oysters and their larvae; he again refutes spontaneous generation
Wrote Letter L-285 of 1696-02-20 to Frederik Adriaan van Reede about the anatomy of the body louse, especially the sexual organs and the louse's rapid reproduction, and his opposition to Jonston's and Kircher's observations on lice
Wrote Letter L-368 of 1700-06-02 to Frederik Adriaan van Reede about the eyes, mouth parts, food, intestines, and eggs of a shrimp
Wrote Letter L-398 of 1701-12-06 to John Somers about the sperm of young cocks living for days outside the cock and whether that was long enough to fertilise a hen's egg
Wrote Letter L-422 of 1704-03-21 to the members of the Royal Society about cochineal and the insects that are the source of this dye
Wrote Letter L-532 of 1716-05-19 to Gottfried Leibniz about muscle and tendon fibers, mammal teats, sperm; did not find eggs in ovaries, Fallopian tube, or womb; cannot imagine how the Fallopian tube could suck sperm; does not know the ovary's function

Related people:

Nehemiah Grew

Christopher Wren

Members of the Royal Society

Pieter Rabus

Frederik Adriaan van Reede van Renswoude

Johann Wilhelm von Pfalz-Neuburg, Elector Palatine

John Somers

Gottfried Leibniz

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Leeuwenhoek's science

Work in Holland

in the 1600's

Specimens: Ovaries

Life in Holland

in the 1600's