Scientist of the Day - Karl Ernst Baer
Paper front cover, De ovi mammalium et hominis genesi epistolam, by Karl Ernst von Baer, 1827 (Linda Hall Library)
Karl Ernst von Baer, an Estonian/Russian biologist and embryologist, was born Feb. 28, 1792, on the family estate in Estonia. Although intended for the military, von Baer wanted to study natural history, and he enrolled in the recently opened University of Dorpat in Estonia, taking a degree in medicine. He then furthered his education at Berlin and Würzburg, where he became interested in embryology.
Portrait of Karl Ernst von Baer, from a voyage narrative of 1852, engraving (Wikimedia commons)
Von Baer obtained a position at Königsberg in 1817, where he eventually became professor of anatomy and zoology. He stayed at Königsberg, and prospered there, but in 1834, he abruptly pulled up stakes and moved to Russia, to St. Petersburg, where he would remain for the rest of his career.
Title page, De ovi mammalium et hominis genesi epistolam, by Karl Ernst von Baer, 1827; cum tabula aenea at the bottom means “with a copper plate” (Linda Hall Library)
Von Baer was not quite a polymath, but he was close, making contributions to zoology, anatomy, botany, anthropology, climatology, geology, and even leading several scientific voyages to northern lands. But today we focus on his first important achievement, which most scholars agree was his greatest – the discovery of the mammalian egg in 1826. We chose to do so because the book in which he announced his discovery was recently acquired by our Library.
Embryologists wielding microscopes had been looking for the mammalian egg ever since the 1650s, when William Harvey claimed that every organism develops from an egg. Some claimed to have found it, but no one did, not for 180 years, until von Baer managed to tease one from the reproductive tract of a female dog. He soon found eggs in other species of mammals, and in 1827, he published a slim quarto, De ovi mammalium et hominis genesi (“Letter on the origins of the mammalian egg and man”), which he wrote in the form of a communication to the Academy of Sciences at St. Petersburg. This is the volume we recently added to our collections.
Dozens of various stages in the development of the mammalian egg, hand-colored engraving based on drawings by Karl von Baer, De ovi mammalium et hominis genesi epistolam, by Karl Ernst von Baer, 1827 (Linda Hall Library)
The book is tall but thin, printed in a large font, and makes its point in just 35 pages, where the first dictum of the ”Conclusio" states: “every organism that is the result of congress between a male and a female develops from an egg.” But most of the book’s impact comes from a hand-colored, engraved plate (fourth image), where there are dozens of images of eggs at various stages of development, including one, fresh from a dog's ovary, that hasn't developed at all (fifth image). The plate is so busy that the caption runs to five full, type-set pages. All of the figures were drawn by von Baer himself.
Detail of fourth image; the tiny white dot in the black band with the number “1” is a canine egg right out of the ovary at natural size; hand-colored engraving based on drawings by Karl von Baer, De ovi mammalium et hominis genesi epistolam, by Karl Ernst von Baer, 1827 (Linda Hall Library)
Von Baer went on almost immediately to begin publishing a much larger work on embryonic development; the first volume appeared in 1828 and the second in 1837. He called his book: Über Entwickelungsgeschichte der Thiere, “On the History of the Development of Animals,” and it would be quite influential in the upcoming debates over Darwinian evolution. We have both volumes of this work in our collections as well, and we will take a look at it, in some future post. Since von Baer attacks what is called Recapitulation Theory (“ontogeny recapitulates phylogeny”), I suppose we first need to introduce one of the pioneers of recapitulation, other than Ernst Haeckel, whom we have already targeted twice.
Statue of Karl Ernst von Baer, Tartu, Estonia (Wikimedia commons)
Haeckel has several statues scattered about, no surprising for a man who is a scientific hero to Prussians, Estonians, and Russians. We show you the one in the Estonian city of Tartu, which is the modern name for what used to be Dorpat, where von Baer launched his university education (sixth image).
William B. Ashworth, Jr., Consultant for the History of Science, Linda Hall Library and Associate Professor emeritus, Department of History, University of Missouri-Kansas City. Comments or corrections are welcome; please direct to ashworthw@umkc.edu.
