Lambert van Velthuysen wrote Letter L-093 of 1679-10-18 to Leeuwenhoek about his delay in responding and gout
This letter is known only by reference in Leeuwenhoek’s reply.
In this letter, Lambert van Velthuysen writes to explain his delay in responding and to affirm that he is still interested in learning about Leeuwenhoek’s observations about gout.
This is the last known letter from Van Velthuysen to Leeuwenhoek. His previous letter to Leeuwenhoek is Letter L-089 of 17 June 1679.
Earlier, in Letter L-086 of early June 1679, Van Velthuysen asked Leeuwenhoek to examine the chalky discharges from gouty skin. Leeuwenhoek responded to Van Velthuysen’s request in Letter L-090 of 11 July 1679 about the tophi of a patient suffering from gout, in which Leeuwenhoek discovered needle-shaped crystals. See also Leeuwenhoek’s reply to the present letter, his last letter to Van Velthuysen, Letter L-095 of 14 November 1679 about the tophi of gouty patients and the causes of gout, in addition to the beneficial effects of drinking tea. Leeuwenhoek sent a copy of that letter to Robert Hooke a week later in Letter L-096 of 20 November 1679.
Letter 52 L-095 of 14 November 1679 to Lambert van Velthuysen:
Seeing from your favour of October 18th that your many occupations are partly the cause of your not having answered before, and also that you are interested in my slight observations and considerations, I again take the liberty to communicate to you my opinion on the gout, formed some time ago.