Untersuchungen Ueber Die Gefaessverbindung Zwischen Mutter und Frucht in den Saeugethieren

Leipzig: J.B. Hirschfeld for Leopold Voss, 1828. ONLY EDITION. Full-page etched plate in contemporary hand color. Rare in tehe original publisher’s cloth with etched paper label affixed to the front panel, remains of spine label; minor foxing, overall in excellent condition. First and only edition of this groundbreaking treatise on placental physiology dedicated to the famous anthropologist S. T. v. Soemmerring (1755-1830) on the 5th anniversary of his doctorate. Building on his published discovery of the mammalian ovum the prior year, Baer here lays out his four laws on epigenetic embryology, which dictate that mammals develop their general characteristics first and their specialized features later. This major step in research on fetal development addressed the issues of how the fetus is nourished and proved that the maternal blood circulation and fetal blood circulation are separate. His scientific findings effectively ended the theory of preformative embryonic development, thus aligning his theories with those of Darwin.

Karl Ernst von Baer (1792-1876) was a Russian scientist credited with establishing the field of comparative embryology. He made a number of specific discoveries in vertebrate morphogenesis related to the development of specific organs or organ systems and was one of the first to recognize that the neural folds represent the rudiments of the central nervous system and form a tube. He was the first to describe and name the five primary brain vesicles and made significant advances in understanding the development and function of the extraembryonic membranes (chorion, amnion, allantois) in chicks and mammals. He also introduced the term "spermatozoa" for so-called "animalcules" (microscopically small organisms) in the semen. In 1826, Baer discovered the mammal's egg in the ovary, ending a search that had begun at least as early as the 17th century. His important contributions paved the way for 20th century advances in developmental biology.

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