Wrote Letter 50 of 1686-05-14 (AB 92) to Members of the Royal Society about gall-nuts found on oak trees and the germination of plants

Date:

May 14, 1686

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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 on ten quarto pages, written by a copyist and signed by Leeuwenhoek, is preserved at the Royal Society (MS. 1912. L 2. 3.).

Leeuwenhoek's summary

From both editions of Cinnaber Naturalis and translated into Latin for all of the editions, some re-titled, of Anatomia Seu Interiora Rerum.

Ontledingen en Ontdekkingen, van de Galnooten, dat deselvige geen vrugt van den Eyken-Boom en konnen genaamt werden, door dien dat hare wasdom alleen veroorzaakt werd, om dat zeker soort van kleine wormkens (die van Vliegen voortkomen, en weder in vliegen veranderen) de Eyke-bladeren doorknagen; uit welke doorknaginge, dan de Galnooten wassen: en soo groeyen ook de Distel-Nooten op de Distels. Van het begin van de planten in de Castanje en Okkernoot, en hoe deselve door strengen haar eerste voedsel of grootwerdinge genieten, gelijk de Dieren in de Baar-moeders doen enz.

Dissections and discoveries of the gall nuts, that of the same cannot be called the fruit of the oak tree, through which only its growth is caused, in order that a certain type of small worms (that come forth from flies, and in turn change into flies) chew through the oak leaves; from which chewing through, the gall nut grows: and so grows also the thistle nut on thistles. Of the beginning of plants in the chestnut and walnut, and how the same enjoy their first nourishment or growth, as do animals in the womb, etc.

Reception in London

About two weeks after it was written, this letter was noted in London at the end of the meeting on May 12/22, 1686 (O.S./N.S.; Birch's History, vol. IV pp. 483, 492):

Another letter of Mr. Leeuwenhoeck was produced, and ordered to be translated.

Six weeks later, they had the translation in hand:

Part of a letter of Mr. Leeuwenhoeck was read, containing his microscopical observations upon the seeds of several Indian plants, shewing how the leaves and the part designed for the root and stem are wrapped up within the said seeds.

Specimens and methods

"What strengthened me in this opinion was my observation"

In this letter, Leeuwenhoek accounted for how he acquired his specimens and how he studied them.

When, in the summer of last year, I was gathering the seed of oak-trees, which we call acorns, in order to examine the beginning of the plant from the said seed, I observed to my surprise that the gall-nuts of the trees were produced from the leaves. This appeared to me the more strange because I had previously thought that the gall-nut was a fruit of a tree, whereas I now saw that this gall-nut was produced only by accident on the leaves of the oak-tree.

What he "previously thought" was not different from the erroneous beliefs of his fellow citizens of Delft. The difference came from Leeuwenhoek's curiousity.

Upon getting home I examined these gall-nuts more closely, and found that each of them had in the centre a small cavity, in which was enclosed a small live worm, which had very little movement.

He didn't stop there.

When, after this, I again went to the Woods of The Hague to continue my investigations, I observed that these worms had changed into small flies.

Always the empiricist reasoning by induction, he concluded:

From these observations I then concluded that these little animals were produced in the following manner ...

He recounted the process as he understood it. Always willing to let evidence change his mind, he wrote several pages later:

But on continuing my investigations, until the latter part of October, I saw that I had been mistaken in my opinion; for I found, and observed very clearly ...

What strengthened me in this opinion was my observation that ...

After getting new evidence that changed his opinion, Leeuwenhoek seemed compelled to seek even more new evidence.

Since then, I have been out again, in the month of January, to gather gall-nuts from the young oak-trees whose branches were low near the ground. ...

I laid a few gall-nuts on my study, and now and then opened one of them. ...

I also enclosed 10 gall-nuts in a wooden box with screwed-on lid, which box I opened at the end of April.

A couple of weeks later, he finally wrote this letter, concluding this very long letter:

I have some further observations ready for despatch; but in order not to burden Your Honours unduly with my excessive writing I will break off here.

Response to other researchers

"In order to obtain greater certainty"

While Leeuwenhoek may have been hampered in his reading because he did not know Latin, he lived in a country with a large, literate, curious public. Many of the books that would be relevant to his research were translated into Dutch. For example, he was studying gall-nuts, so he turned to a contemporary expert: Jean Baptiste Tavernier (1605-1689).

In order to obtain greater certainty in these observations and considerations, I learned upon inquiry that the best species of gall-nuts in current use in this country are brought to us from Aleppo. I thereupon looked up the travels of Mr. Tavernier, to see what that gentleman had to say about the germination of the gall-nut. In his third book, p. 232, speaking about his journey around Aleppo he says: The mountains are covered with oak-trees which produce gall-nuts; one also finds some which, in addition to gall-nuts, also bear acorns

But from the foregoing observations it is no longer surprising that an oak-tree can bear gall-nuts and acorns at the same time, since all oak-trees can produce gall-nuts, providing such species of flies are in the neighborhood from whose eggs worms are born which can use oak-leaves for their food.

In order to learn still more about this subject I took several gall-nuts which had been imported here, and which are being used here by silk- and other dyers.

In 1682 De zes reizen van de heer J. Bapt. Tavernier (title page on right; click to enlarge) was published in Amsterdam in a Dutch translation by J.H. Glazemaker.

Later in the letter, he addressed the impossibility of the transplantation of the embryo of the seed of a plant into the seed of another plant.

A certain prominent gentleman, who had understood from me what I have said heretofore, encouraged me to accomplish this; adding that, even if one were successful with only one out of many seeds, that would be something which had never been seen or heard about.

I did think to myself that this would be impossible to realize - as, in fact, I have experienced since then -; but since there are few people with any knowledge of the embryo of trees and plants, I will here indicate how the matter lays with regard to the germ both of the chestnut and of the walnut.

After discussing four figures, Leeuwenhoek concluded that, indeed,

From these recorded observations ... it appears to me to be impossible to take the embryo of the plant out of a chestnut, and place it in the walnut in the spot where the beginning of the plant of the latter nut has lain, in order thereby to make the germ of the chestnut grow inside the walnut. ...

All this being as it is, it is clear to us that there are no means available to us to take the embryo of a plant from its seed, and cause it to unite with the mealy substance of another seed.

The public and their opinions

"He had dismissed one of his maids, because she was full of lice."

In the text, Leeuwenhoek gave two examples of how his observations affected the people he knew in Delft. He mentioned Letter 46 of July 13, 1685, in which he concluded that it was not "possible to take the beginning of a plant from a body which we call 'seed', and unite it with, or add it to, another seed, at the place where the beginning of a different plant had lain." Nevertheless,

He then gave several pages of observations and concluded:

It is clear to us that there are no means available to us to take the embryo of a plant from its seed, and cause it to unite with the mealy substance of another seed.

His second example involved another unnamed gentleman:

I am quite aware that there are many people who firmly believe, and maintain not only that vermin can develop from decayed matter, but even that lice may originate from sweat; and when, some time ago, a certain eminent and learned gentleman wanted to affirm this to me, saying that he had seen several instances of it, I replied that this was pure imagination ....

I was absolutely certain that it was just as impossible for a louse or a flea to come into being without procreation as it was for a horse or an ox, or some such animal to be born from the decay and corruption of a dung-heap; and that, although we provide our body with clean linen more than once a week, and imagine that we do not associate with people who have lice, yet we can get such vermin from our maid-servants, or from those who make our beds, and who have the said vermin, and might very easily pass some of it on to the bed-linen.

The gentleman in question was satisfied with this last remark, and I heard afterwards that he had dismissed one of his maids, because she was full of lice.

"The miraculous power to cure of haemorrhoids or piles was to me incredible"

His second example involved another unnamed gentleman:

I must not omit to mention here that, in the late summer of last year, I was shown a number of knob-like excrescences of various sizes, which had been gathered from thistles, for which reason they are called ‘thistle-nuts’. These so-called thistle-nuts are carried by many people in this country in their pockets, with the idea that so long as they keep them there they will not be troubled with hemorrhoids or ‘piles’, especially if one throws away the old nuts every year, and replaces them with newly-grown ones (which, it is said, do not grow in our province).

And some of these people even elaborate on this, saying: there is a worm inside the nut; and so long as that worm is alive, so long will the nut perform its action, and once the worm is dead, it is all over with the power of the nut.

As soon as I saw these galls I concluded that they had also been produced accidentally; and the use of them, on account of the miraculous power to cure of haemorrhoids or piles, attributed to them, was to me incredible; the more so when, on coming home, I examined them, and found ...

Figures

The original drawings are lost. The scans here came from Opera Omnia, the 1722 fourth edition of Arcana Naturae Microscopiorum.

In the text, Leeuwenhoek noted "I have thought fit to have drawings made of the gall-nuts as they grow on the leaves, and shown here in fig. 1." He did not say anything more about who drew the figures, but all of them with the exception perhaps of Fig. 3 and Fig. 4 seem beyond Leeuwenhoek's skills.

He spoke of collecting his gall nuts and thistle nuts from the nearby Haagse Bos. It was a five-mile trip via the regular Delft-Den Haag ferry service.

However, the gallnuts that illustrated this letter, twice the size of the local specimens, were imported from Aleppo.

The mezzotint portrait of Leeuwenhoek by Johannes Verkolje, dated 1686, had the gallnuts (detail on right; click to enlarge) in Fig. 1 on the worktable in front of Leeuwenhoek. Note also that Leeuwenhoek is holding a wide magnifying glass with three lenses.

Publication history

Related sources, especially Philosophical Transactions, and first editions only of Leeuwenhoek's volumes of letters. For later editions see Related events under Learn more.

Year	Author	Title
1682	Tavernier, J. B.	De zes reizen van de heer J. Bapt. Tavernier
1686	Leeuwenhoek, A. van	Cinnaber Naturalis
1687	Leeuwenhoek, A. van	Anatomia Seu Interiora Rerum
1961	Leeuwenhoek, A. van	Alle de Brieven. The Collected Letters. Volume 6
1961	Schierbeek, A.	The history of the investigation into the genesis of gall-nuts

Other publications:

By the time the Royal Society received this letter, Edmond Halley was editor of Philosophical Transactions. This letter was never published there. Nor was it published anywhere else before 1800.

Notes

To describe the little worms in the gallnuts, Leeuwenhoek used the word tonneken, which translates literally to little barrels. He was probably trying to expressed the cross-ribbed structure of what we would now call the pupa.

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Period 4 - 1694-1702

Period 2 - 1679-1686

Structure of the letters in Period 2

1686: Royal Society

Specimens: Sperm

Spontaneous generation

Related people:

Members of the Royal Society

Related events:

Date	Event
January 1, 1686	Published Cinnaber Naturalis (Natural Cinnabar), Letters 48 - 52
May 22, 1686	The Royal Society read part of Letter 90 [49] of 2 April 1686
January 1, 1687	Published Anatomia Seu Interiora Rerum (Interior Anatomy), 19 Letters from 28 - 52
June 18, 1687	The Royal Society read part of Letter 50 of 1686-05-14 about gall nuts
January 1, 1696	Published Arcana Naturae Microscopiorum (Nature's Mcroscopical Mysteries), 19 Letters from 28 - 52 (2nd)
January 1, 1708	Published Arcana Naturae Microscopiorum (Nature's Mcroscopical Mysteries), 19 Letters from 28 - 52 (3rd)
January 1, 1713	Published Cinnaber Naturalis (Natural Cinnabar), Letters 48 - 52 (2nd)
January 1, 1722	Published Opera Omnia, seu Arcana Naturae Microscopiorum (The Works, or Nature's Microscopical Mysteries), 25 Letters from 28 - 60 (4th)

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Letter 50 Figures 1-9

Wrote Letter 50 of 1686-05-14 (AB 92) to Members of the Royal Society about gall-nuts found on oak trees and the germination of plants

"What strengthened me in this opinion was my observation"

"In order to obtain greater certainty"

"He had dismissed one of his maids, because she was full of lice."

"The miraculous power to cure of haemorrhoids or piles was to me incredible"

Figures

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Letter 50 Figures 10-15