Letter, from Antoni van Leeuwenhoek to Nehemiah Grew, dated at Delft Signed autograph Discussing Regnier de Graaf's theories about ovulation in women; further observations about sperm of rabbits and dogs; concerning the structure of bone and hair Text refers to eight figures of male sperm, bone and hair but only three ink figures of sperm, numbered Figures 1, 3, 4 , are attached English translation see EL/L1/37 Transcribed and translated in 'Alle de brieven van Antoni van Leeuwenhoek', edited, illustrated and annotated by Committee of Dutch Scientists, vol 2, p 355 English extract in 'Philosophical Transactions', vol 12, issue 140, p 1002 B&W negative, of one drawing, Box N101. IM/005318 31 May 1678