Govert Bidloo wrote to Leeuwenhoek about little animals in sheep's livers

March 21, 1698

This letter was published in 1698 by Henrik van Kroonevelt (who lived next door to Leeuwenhoek) with the title

Brief van G. Bidloo aan Antony van Leeuwenhoek: Wegens de dieren, welke men zomtyds in de lever der Schaapen en andere beestern vind

Letter of G. Bidloo to Antony van Leeuwenhoek: About the animals which are sometimes found in the liver of Sheep and other beasts


Med Hist. 1974 Apr; 18(2): 203–204

When an English translation of the letter by J. Jansen was published (Nieuwkoop: De Graaf) in 1972, an anonymous reviewer for the journal Medical History wrote:

Govert Bidloo (1649-1713), anatomist and surgeon, had made microscopic observations on certain animalcules and ova found in the bile passages, and now identified as F. hepatica. He was not the first to note the parasites, for his study contains abundant references to the work of predecessors, but he made surprisingly accurate descriptions and references (along with many errors). He disclosed his findings and conclusions in a letter to Leeuwenhoek.

Bidloo describes and illustrates the morphology, and thus permits us to compare his findings with the more precise knowledge of modem biology. Bidloo made some erroneous statements and drew some erroneous conclusions, but error, when studied in its context, is perhaps the best way of tracing the progress of science. His speculations regarding the development of the parasite and the relationship of these and other worms to disease are extremely interesting and throw much light on basic concepts of seventeenth-century medicine. At the same time the text obliquely illuminates the personality of the author and the customs of the times, in regard to communications.