Letter, from Antoni van Leeuwenhoek to Henry Oldenburg, dated at Delft Signed autograph An account of the structure of hair and how it grows; theory about curly hair; observations of the structure of cow's skin; observations of the membranes of eggs Ink figure of Leeuwenhoek' s facial hair after shaving See EL/L4/29 for information about rasors for shaving Transcribed and translated in 'Alle de brieven van Antoni van Leeuwenhoek', edited, illustrated and annotated by Committee of Dutch Scientists, part 1, p 348 For summary see 'The correspondence of Henry Oldenburg', ed and trans by A Rupert Hall & Marie Boas Hall, vol 12, p 192 22 February 1676