Extrait Critique
Published posthumously, five years after Hartsoeker died.
The final section is titled:
Extrait Critique des Lettres de M. Leeuwenhoek par feu M. Hartsoeker
Excerpt Critics of Mr. Leeuwenhoek Letters by the late Mr. Hartsoeker
Hartsoeker died two years after Leeuwenhoek. He wrote in negative, derisive terms about Leeuwenhoek, his observations, his methods, and his personality.
"Ce qui me surprend, c'est qu'une illustre societe a pu entretenir un commerce de lettres assez regulier avec un homme comme lui, qui avait des yeux, des verres et beaucoup de patience, mais peu ou point de bon sens!"
"What surprises me is that an illustrious society [Royal Society] was able to maintain a fairly regular correspondence with a man like himself, who had eyes, glasses and much patience, but little or no common sense!"
Dobell (p 70):
Hartsoeker was a man of undoubted ability, but quarrelsome and arrogant and in every way the very antithesis of Leeuwenhoek. He attacked and found fault with everybody he envied -- not only Leeuwenhoek, but also Newton, Leibniz, and even Christiaan Huygens (who had befriended him) -- and his foolish criticisms and personal complaints are now best consigned to the oblivion which they deserve.
The Extrait Critique discusses every one of the 165 letters that Leeuwenhoek published in Dutch and Latin, ending with Send-Brieven. The 70-page section begins (my translation):
As the letters that the late Mr. Leeuwenhoek wrote in a base and pointless style to various people, especially to the Royal Society of London of which he was a member, contain among a quantity of useless and chimerical observations, some very good and which serve for the advancement of the sciences, I have long had the intention to publish them in abbreviated form, add some of my own observations to it, and comment on some of his. Never has a book cost me so much, because these letters fill more than two thousand four hundred quarto pages and I was obliged to take the trouble to examine them from cover to cover, and even to make a new quantity of observations which he reports as very true, and which I had, however, reason to doubt.
The next to last paragraph summarizes the final four letters: "nothing remarkable to report". The final paragraph:
Everything he says has been said and repeated a thousand times, so much so that they are just so many lost words; & as far as the figures are concerned, nothing at all, representing only confused features.