Wrote Letter 58 of 1687-09-09 (AB 103) to Members of the Royal Society about ant eggs, larvae and its development, feeding, sting, cocoon and nest

September 9, 1687
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Text of the letter in the original Dutch and in English translation from Alle de Brieven / The Collected Letters at the DBNL - De Digitale Bibliotheek voor de Nederlandse Letteren.

The original manuscript, written and signed by Leeuwenhoek, is preserved at the Royal Society (MS. 1923, EL.L2.8).

What motivated him?

Curiousity about the world around him. What something happened, he wanted to know exactly what it was. As an off-hand remark in this letter, Leeuwenhoek gave an indication of how long he had been using lenses to investigate nature.

These swellings, which I received from the ants while investigating their reproduction, caused me more pain than they gave me at any other time in the whole of my life, although I have many times been stung by them: For it is now about twenty years ago that, having once been stung hard by the same, I then discovered that the abdomen was provided with a sting.

Twenty years before this letter was written in 1687 was 1667, a year or so after he made a short visit to England. There, he used a lens to look more closely at the chalk on the coast. How powerful were his lenses then? The lens best suited to looking at chalk and at an ant's body would have been much less powerful than the lenses Leeuwenhoek later used for looking at little animals in canal water in the 1670's.


The original drawings are lost. The Dutch and Latin editions that Leeuwenhoek published used the same plate with all eight figures. The one below (click to enlarge) came from the 1730 fourth edition of Continuatio Epistolarum, as did the images on the sidebar. In the text, Leeuwenhoek noted that someone else drew the figures.

Among the smallest parts that I took away from the ants, or sought out from amidst the earth, I found several eggs which were so tiny that I could not recognize them with the naked eye. I have put such an egg before the microscope, and I had it drawn, as is shown here in fig. 2. ABC.

Plate from
Continuatio Epistolarum

Figures 1 - 8

He also did something he rarely did. Still discussing Fig. 2, he spoke of a tool that he used, in this case a ruler.

Furthermore, in order to illustrate the minuteness of such an egg, I laid the same on a graduated ruler; and I am bound to say that ninety diameters of the thickness of one egg do not amount to the length of one inch.

As he had in several recent letters, Leeuwenhoek implied that he and his draughtsman did not always see the same things when he noted that in this case the draughtsman did see what Leeuwenhoek wanted to illustrate. Referring to Figs. 4 and 5, he wrote:

I also had one of these eggs drawn, because the draughtsman was able to recognize all the worms' members in this egg. ... I further put before the microscope one of the Worms which, during the aforesaid time, had crept out of the Eggs, and had it drawn just as it appeared.

Discussing Fig. 6, he noted that the figures illustrated only the beginning of the life cycle of the ant. Oddly enough for someone who had so much difficulty with public acceptance of his ideas, he spoke of how easy these creatures were to imagine.

These worms lie a bit curled up when they are young: But by the time they have grown to almost full-grown size; they begin to straighten out. This worm is drawn through a much less magnifying glass than that through which the preceding figures are drawn, so that one may surely conclude from this how small the eggs are. I might illustrate the size of a full-grown worm through the microscope; but I think this unnecessary, because one can easily imagine what a worm is like that retains the same figure when it is ten times larger.

Other publications

While the Royal Society did not publish this letter in Philosophical Transactions, it was extracted twice in foreign journals, as were all the letters in Vervolg der Brieven, Letters 53 through 60. In the year after it was written, Jean Le Clerk published an excerpt, including four of the eight figures, in Bibliothèque universelle et historique, vol. 9, p. 152-157.

In 1689, Otto Mencke pubished a short extract, without any figures, in Acta eruditorum, vol. 8, pp. 172-173.