Wrote Letter 5 of 1674-07-06 (AB 9) to Henry Oldenburg

July 6, 1674
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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

Leeuwenhoek wrote this letter to Henry Oldenburg about sweat, hair, fat, and tears; improved capillary tubes.

He mentions that he sent his letter of 1674-06-01 along with glass tubes and specimens via Mr. Adriaen Boogaert, seigneur of Belois and a director of the VOC in Delft.

2 ink drawings in the margins of the text.

Figure 5

I have formerly sent you my way of seeing the motion of the Globuls in the Crystallin liquor of the Blood: Having since contrived a more convenient Glass-pipe for that purpose, I cannot but give you and your Curious Friends notice thereof;

A B is a hollow Glass-pipe from B to O, about the thickness of a coarse horse-hair; from O to D, about the thickness of a Pigeons-quil, and the thickness from D to A somewhat slenderer. 'Tis open on both its ends, A and B: Into this pipe I brought some Blood.

Figure 6

A and B are two Globuls of Fat, that are formed first, and the third being a forming, and to be placed between and above A and B, it will take the form of C, and so make up the triangular body F D E. ...

I have lately observ'd, that each buble or globul of Fat consists of more than a thousand small Globuls. Yet I am apt to believe, that those that have not seen the Globuls in Blood, Hair, Bone, &c. will not satisfie themselves about seeing the Globuls in the Globuls of Fat, because of their extraordinary minuteness.