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Donkey milk knowledge archive · Historical source
Joseph König (1904): donkey milk in the standard work of food chemistry
In 1904 the Münster chemist Joseph König summarised in the second volume of his handbook what was known about donkey milk: in its ratio of nutrients it came closest to human milk. A table gives the mean of 25 analyses.
- Author
- Joseph König (1843–1930), professor at the University of Münster and head of the agricultural chemistry experimental station
- Work
- Chemie der menschlichen Nahrungs- und Genussmittel, vol. 2: Die menschlichen Nahrungs- und Genussmittel, ihre Herstellung, Zusammensetzung und Beschaffenheit, 4th revised edition
- Passage
- Section “Milk”, subsection “Milk of solipeds”, no. 2 “Donkey milk”, pp. 662–663, with table on p. 663
- Time & place
- 1904 (4th edition, vol. 2) · Münster, Westphalia (published in Berlin)
- Type of source
- Scientific handbook (food chemistry)
In the original words
What the original says
Die Eselmilch, welche in ihrem Nährstoffverhältniss der Frauenmilch am nächsten steht, wird an manchen Orten, so besonders in Frankreich, als Ersatz der Muttermilch für Kinder verwendet.
Donkey milk, which in its ratio of nutrients comes closest to human milk, is [according to König] used in some places, especially in France, as a substitute for mother’s milk for children.
Die Eselmilch hat angeblich die kleinsten Milchfettkügelchen und eine weisse Farbe mit einem Stich ins Bläuliche.
Donkey milk is said to have the smallest milk-fat globules and a white colour with a bluish tinge.
Sie schmeckt fade süsslich, ähnlich wie gewässerte Kuhmilch.
It tastes insipidly sweet, rather like watered-down cow’s milk.
English rendering: our own translation by the DON DONKEY’S editorial team, following the sense of the text.
A look at the original
What the passage looks like
Page 662 of volume 2 of the 4th edition of König’s “Chemie der menschlichen Nahrungs- und Genussmittel” (Berlin 1904), with the section “Milk of solipeds” and the footnote on Varro and Poppaea.
The page comes from a freely accessible digitised copy. Click to open the passage at the library.
University of California, San Francisco, Library; Digitalisat via Internet Archive; gemeinfrei
Background
Who, when, what kind of text
Joseph König headed the agricultural chemistry experimental station in Münster and taught at the university there; he is regarded as one of the founders of food chemistry in Germany. His multi-volume handbook first appeared in the late 1870s and was expanded over decades. It collected published analyses of foods from all over Europe and was a central reference work for food chemists.
The second volume of the fourth edition deals with the individual foods. In the long chapter on milk, cow’s, goat’s and sheep’s milk are followed by the milk of buffalo, camel and reindeer and then by the “milk of solipeds”: mare, donkey and mule. The description of each kind of milk combines origin and use with analytical values from the literature.
Content
What the source reports about donkey milk
König presents donkey milk as the milk closest to human milk in its ratio of nutrients and reports that, especially in France, it was used as a substitute for mother’s milk for children. Like mare’s milk, it was also regarded as a wholesome food for consumptives and other patients. Donkey milk is not a substitute for breast milk or infant formula; infant feeding belongs in medical hands.
In a footnote König traces this esteem back to antiquity, to Varro and to Pliny, according to whom Poppaea is said to have always taken 500 jennies with her. On its properties he writes that donkey milk supposedly has the smallest fat globules, is white with a bluish tinge and tastes insipidly sweet.
The table on p. 663 gives as the mean of 25 analyses: 90.12 % water, 0.79 % casein, 1.06 % albumin, 1.37 % fat, 6.19 % sugar and 0.47 % ash. König adds that the values vary widely, for fat between 0.2 and 2.82 %.
At a glance
Figures & facts from the source
Timeline
Where this source stands in the history of donkey milk
Each dot is a source from our knowledge archive – from Greek antiquity to the present day.
Critical assessment
How reliable is this source?
Source value
König’s handbook was the reference work of German food chemistry. The data can be checked page by page as a scan. König did not analyse donkey milk himself but collected and averaged analyses published by others.
Careful wording
König writes “supposedly” where he does not consider information certain, for instance on the size of the fat globules. He reports the healing effect as a widespread opinion and derives it from ancient tradition, not from his own experiments.
Today’s assessment
The analytical values are of the same order as modern measurements, but the methods were less precise. The use as a substitute for mother’s milk is a historical finding; donkey milk is not a substitute for breast milk or infant formula.
Our assessment
With König, around 1900, donkey milk moves from medicine into laboratory analysis: percentages now count instead of effects. That this standard work was written in Münster, in the heart of the Münsterland region that is also our home, makes the passage especially vivid for us.
References
Sources to check
- Primary sourceJ. König, Chemie der menschlichen Nahrungs- und Genussmittel, vol. 2: Die menschlichen Nahrungs- und Genussmittel, 4th revised ed., Berlin: Julius Springer 1904, p. 662, section “Milk of solipeds” (Internet Archive; catalogued as 1903)
https://archive.org/details/chemiedermenschl02knig/page/n693/mode/1up - SupplementaryFollowing page 663 with the end of the description and the table on the composition of mare’s, donkey and mule milk
https://archive.org/details/chemiedermenschl02knig/page/n694/mode/1up
More sources and studies in the research archive. Summarised by the DON DONKEY’S editorial team, as of November 2026.