De Ovi Mammalium et Hominis Genesi

The work De Ovi Mammalium et Hominis Genesi (1827), meaning "On the Mammalian Egg and the Origin of Man," was published by Karl Ernst von Baer. In this publication, Baer announced his discovery of the mammalian ovum, establishing that mammals, including humans, develop from eggs. This work was foundational to the new science of comparative embryology. Baer's research opposed the idea that embryos of one species pass through stages resembling adults of other species, instead emphasizing that embryos of the same species resemble each other, with younger embryos showing greater similarity. This concept aligns with his epigenetic view that development progresses from simple to complex forms. Baer's work laid the groundwork for modern embryology by demonstrating epigenesis and identifying the germ layers from which embryonic organs develop.123