Wrote Letter 34 of 1681-11-04 (AB 66) to Robert Hooke about hog bristles, shedding hair, blackheads; living little animals in excrement, horse urine, clay, and gout

November 4, 1681
Standard reference information
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Text of the letter in the original Dutch and in English translation from Alle de Brieven / The Collected Letters at the DBNL - De Digitale Bibliotheek voor de Nederlandse Letteren.

The original manuscript on thirteen quarto pages, written and signed by Leeuwenhoek, is preserved at the Royal Society (MS. 1883. L 1. 64). It has four figures.

Leeuwenhoek had not written any letters for almost a year, that is, most of 1681. During that year, he sat for Cornelis de Man's Anatomy Lesson of Dr. 's Gravezande. In April, his cousin Jannitgen Huijchs Leeuwenhoek died. In June, another cousin, Maria Maertens Leeuwenhoek, married Leeuwenhoek's Staduis colleague Jan den Appel. A week after that, the city's other camerbewaarder, Daniel Bogart, was buried. He and Leeuwenhoek had worked together for the mayors and magistrates for twenty years.


Plate from
Arcana Naturae Microscopiorum

Figures 1 - 4

The four original drawings, in red chalk, are preserved at the Royal Society. The Dutch and Latin editions that Leeuwenhoek published used the same plate with all four figures. The one below (click to enlarge) as well as the scans on the left sidebar came from the 1708 third edition of Arcana Naturae Microscopiorum.

In the text, Leeuwenhoek stated that he drew Fig. 4 and implied with "also" that he drew all four of these hair sections.

Fig. 4 is a piece of an entirely black hog's bristle, also cut across; as it was very interesting to see, I also made a drawing of it. In this hair the fibres, cut transversely and marked by me, were very distinct, even through an ordinary microscope; however, I drew them much bigger than they actually are (in proportion to the circumference of the hair) because I found it impossible to draw them properly on so small a scale.