Wrote Letter L-467 of 1708-08-28 to the members of the Royal Society about how an eel's heart and the valves in the vien of its tail work; his own pulse and pulsation of the heart of an eel and a pike
Date:
August 28, 1708
The original manuscript on eight quarto pages, written and signed by Leeuwenhoek, is preserved at the Royal Society (MS. 2073, L 4. 22). The original drawings are lost.