Specimens: Sperm

Leeuwenhoek observed sperm in various animals for forty years in around thirty letters, around a tenth of all his letters.

 


1677 November -- Letter 35 (AB22)

human sperm

 

 


1678 March 18 -- Letter 38 (AB24)

dog, rabbit, stallion and bull, theory of impregnation

 

 


1678 May 31  -- Letter 39 (AB25)

rabbit, dog

 

 


Letter 42 [27] of 21 February 1679, cod;

 

 


Letter 43 [28] of 25 April 1679, vol. 3, cod, pike, more than 10,000 little animals in every small sand-grain of matter, hare, cock, estimated 50,000 sperm in a sand grain of matter, calculated 13,385,000,000 human beings on earth and 150,000,000,000 sperm in cod milt;

 

 


Letter 54 [29] of 12 January 1680, perch, bream, roach and tench;

 

 


Letter 57 [30] of 5 April 1680, rat, origin of sperm;

 

 


Letter 65 [33] of 12 November 1680, horse, may-bug, dragon-fly, grasshopper, fly, flea and gnat;

 

 


Letter 70 [37] of 22 January 1683. vol. 4, number of sperm repeated from Letter 43 [28];

 

 


Letter 72 [38] of 16 July 1683, frog, rabbit and dog;

 

 


Letter 84 [45] of 30 March 1685, vol. 5, most detailed theory of impregnation;

 

 


Letter 85 [46] of 13 July 1685, Collected Letters, vol. 5, similarities of plant and animal generation.

 

 


Letter 92 [50] of 14 May 1686, vol. 6, L. included a passage from Letter 85 [46] about the germination of plants.

 

 


Letter 102 [57] of 6 August 1687, vol. 7, calandar ;

 

 


Brief 109 [64] of 24 August 1688, calculated sperm in cod roe;

 

 


Letter 134 [80] of 2 March 1694, vol. 10, no sperm found in any eggs;

 

 


Letter 157 [95] of 18 September 1695, vol. 11, mussels;

 

 


Letter 170 [103] of 16 July 1696, vol. 12, oysters;

 

 


Letter 214 [128] of 9 July 1700, vol. 13, cock;

 

 


Letter 219 [134] of 26 October 1700, aphids;

 

 


Letter 220 [135] of 25 December 1700, ram, man, cock, objections to Hartsoeker;

 

 


Letter 224 [137] of 15 April 1701, cod, pike, ram;

 

 


Letter 231 [142] of 6 December 1701, vol. 14, cock;

 

 


Letter 232 [143] of 20 December 1701, spiders;

 

 


Letter 236 [146] of 20 April 1702, silk moth;

 

 


Letter 287 of 18 August 1711,

 

 


 

vol. 17, ram;

 

 

 


Letter 292 of 1 March 1712, whale;

 

 


Letter 317 [XVIII] of 28 September 1715, public acceptance of his theory of procreation, perch, cod; and

 

 


Letter 326 [XXIII] of 19 May 1716, impregnation.

 

 


In three letters, L. defended his ideas.

 

 


Letter 196 [113] of 17 December 1698, defended the priority of his ideas about reproduction against Hartsoeker, quoting extensively from Letter 35 [22] of November 1677 and Letter 38 [24] of 18 March 1678 (see above);

 

 


Letter 200 [116] of 9 June 1699, defended his idea of sperm against Dalenpatius.

 

 


Letter 201 [117] of 23 June 1699, defended his idea of generation and reproduction of sperm against Lister;

 

 


Further reading

For discussion of L.'s ideas on spermatozoa see Ruestow's, "Images and Ideas".

Also, Schierbeek's Leven en Werken, vol. 2, pp. 295-385 and Measuring the Invisible World, pp. 80-107; Lindeboom's "Sexual Reproduction", Cole's, "Leeuwenhoek's ... researches", pp. 8-12, and Ruestow's Microscope in the Dutch Republic, pp. 201-259.

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