Letters written by Leeuwenhoek during Period 3

Alle de Brieven / Collected Letters has over 350 letters. However, only those in this chronology that Leeuwenhoek designated Letter 1, Letter 2, etc. did he consider to contain publishable microscopic observations.

Date
March 1, 1687 Wrote Letter L-185 of 1687-03-01 to James II, King of England, as the dedication for one of his volumes
April 4, 1687 Wrote Letter L-186 of 1687-04-04 to the members of the Royal Society about the structure of the teeth of elephants, pigs, humans, oxen, and horses and about toothache
May 9, 1687 Wrote Letter L-187 of 1687-05-09 to members of the Royal Society about the structure of 'stone' of the medlar and the coffee bean and acid in plants
June 13, 1687 Wrote Letter L-188 of 1687-06-13 to members of the Royal Society about wheat and the seeds from a variety of plants
July 11, 1687 Wrote Letter L-189 of 1687-07-11 to members of the Royal Society about eggs of silkworms and caterpillars and humans' squinting and a theory for its cause
August 6, 1687 Wrote Letter L-190 of 1687-08-06 to members of the Royal Society about the calander and the louse and against spontaneous generation
September 9, 1687 Wrote Letter L-192 of 1687-09-09 to members of the Royal Society about ant eggs, larvae and its development, feeding, sting, cocoon and nest
October 17, 1687 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
November 28, 1687 Wrote Letter L-194 of 1687-11-28 to members of the Royal Society about his discovery that cochineal was an insect and his experiments with cinchona bark
May 25, 1688 Wrote Letter L-196 of 1688-05-25 to members of the Royal Society about a medicinal root and bladderstones
July 6, 1688 Wrote Letter L-197 of 1688-07-06 to the members of the Royal Society bezoar stone, monkey stone, gout tubercles, and red coral and white coral
August 3, 1688 Wrote Letter L-198 of 1688-08-03 to the members of the Royal Society about plaster, alabaster, gypsum, Muscovite glass, cobblestone, shell lime, masonry mortar, lime, cement, sand stone, and slate
August 24, 1688 Wrote Letter L-199 of 1688-08-24 to the members of the Royal Society about gnats, horseflies; growth of branches, germination of wheat plants, the soft and hard roe of cod, and the number of sperm in a cod's soft roe
September 7, 1688 Wrote Letter L-200 of 1688-09-07 to the members of the Royal Society about development of the eggs of green frogs, blood circulation in frogs and the tail fin of roach and bream, and the shape of red blood cells
September 23, 1688 Wrote Letter L-201 of 1688-09-23 to Melchisedec Thevenot, a cover letter for a copy of Leeuwenhoek's Letter L-200, published separately as Den waaragtigen omloop des bloeds.
January 1, 1689 Wrote Letter L-202 of sometime in 1689 to Antonio Magliabechi, a cover letter for one of his books
January 12, 1689 Wrote Letter L-203 of 1689-01-12 to Robert Boyle, a cover letter for Continuatio epistolarum and a copy of Letter L-204
January 12, 1689 Wrote Letter L-204 of 1689-01-12 to the members of the Royal Society about his observation of the circulation of the blood in a variety of fish as well as a description of the construction of his ‘eel spy-glass’ and the slime on the skin of an eel
April 1, 1689 Wrote Letter L-206 of 1689-04-01 to the members of the Royal Society
October 1, 1689 Wrote Letter L-207 of October 1689 to Christiaan Huygens about sending books to father Constantijn Huygens in London
September 18, 1691 Wrote Letter L-210 of 1691-09-18 to Antonio Magliabechi about
November 27, 1691 Wrote Letter L-212 of 1691-11-27 to the members of the Royal Society about blood, chyle, and an experiment to discover the volume of water when it is cold and when it is heated
January 4, 1692 Wrote Letter L-213 of 1692-01-04 to the members of the Royal Society about bladder and kidney stones and a chalk-like substance from a gout stone
February 1, 1692 Wrote Letter L-214 of 1692-02-01 to the members of the Royal Society about various peppers and their taste, tea and its effects of tea on digestion, and Spanish fly
March 7, 1692 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
April 22, 1692 Wrote Letter L-217 of 1692-04-22 to Richard Waller about the construction of an air pump and experiments with different liquids, seeds and small stones in urine, a hog's hair in the skin of a child, and grains of wheat
June 24, 1692 Wrote Letter L-218 of 1692-06-24 to the members of the Royal Society about more experiments with his air-pump, the structure of and blood in an insect's wing, a grey owlet moth, and the wing of a very small fly
August 12, 1692 Wrote Letter L-220 of 1692-08-12 to the members of the Royal Society about the shaft of a bird's feather as used in a quill, the lens and cornea of the human and calf eyes, 'wood-pipes' in different species of wood, bulrushes, and pine and lime wood
September 16, 1692 Wrote Letter L-221 of 1692-09-16 to the members of the Royal Society about little animals in dental tartar, theories of eel reproduction, worms in eel intestines, and blood vessels in grasshoppers
September 23, 1692 Wrote Letter L-222 of 1692-09-23 to Mary, Queen of Great Britain, the dedication to Derde Vervolg der Brieven
July 1, 1693 Wrote Letter L-225 of 1693-07-01 to Richard Waller, cover letter for a volume in Latin and confirmation of receipt of Letter L-224
October 15, 1693 Wrote Letter L-228 of 1693-10-15 to the members of the Royal Society about colors and the life cycle of fleas
October 27, 1693 Wrote Letter L-229 of 1693-10-27 to Pieter Rabus about procreation of the flea, the leather-jacket, and the mite
December 8, 1693 Wrote Letter L-230 of 1693-12-08 to Richard Waller, a cover letter
December 20, 1693 Wrote Letter L-231 of 1693-12-20 to the members of the Royal Society about spiders, lice, and mites
January 19, 1694 Wrote Letter L-232 of 1694-01-19 to Richard Waller as a cover letter for Letter L-231
January 24, 1694 Wrote Letter L-233 of 1694-01-24 to the members of the Royal Society about tapeworms and salt and sand in cod intestines
February 12, 1694 Wrote Letter L-235 of 1694-02-12 to Richard Waller as a cover letter for Letter L-233
February 24, 1694 Wrote Letter L-236 of 1694-02-24 to the members of the Royal Society about his experiments with solid phosphorus
March 2, 1694 Wrote Letter L-239 of 1694-03-02 to the members of the Royal Society about ear wax and hair, body hair, the amount of sweat secreted from the human body, and the possibility that sperm might penetrate the ovum
March 19, 1694 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
April 2, 1694 Wrote Letter L-241 of 1694-04-02 to the members of the Royal Society about the tongue of an ox and a pig and the heart of a sheep, ox, duck, chicken and cod
April 30, 1694 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
May 26, 1694 Wrote Letter L-244 of 1694-05-26 to Richard Waller, cover letter for copy of Vierde Vervolg der Brieven