Baer, Karl Maksimovich

(also Karl Ernst von Baer). Born Feb. 17 (28), 1792, on Piep estate, now Paide Raion, Estonian SSR; died Nov. 16 (28), 1876, in Tartu. Russian naturalist; founder of embryology.

Baer graduated from the University of Dorpat (Tartu) in 1814. In 1817 he began working at the University of Königsberg. In 1826 he became an associate member, in 1828 academician, and in 1862 honorary member of the St. Petersburg Academy of Sciences. He returned to Russia in 1834 and worked at the St. Petersburg Academy of Sciences and the Medico-Surgical Academy from 1841 to 1852.

Baer discovered the ovum in mammals and man (1827), made a detailed study of the embryogeny of the chick (1829 and 1837), and investigated the embryonic development of fish, amphibians, reptiles, and mammals. He discovered an important stage of embryonic development, namely, the blastula. He also traced the fate of leaflike germ layers and the development of fetal membranes. Baer established that (1) embryos of higher animals resemble only the embryo and not the adult forms of lower animals and (2) in the process of embryonic development the characteristics of the phylum, class, order, family, genus, and species manifest themselves in succession (Baer’s laws). He investigated and described the development of all the principal organs of vertebrates, including the notochord, brain, spinal cord, eyes, heart, excretory system, lungs, and digestive tract. The facts discovered by Baer in embryology were proof of the groundlessness of the preformation theory. He also worked fruitfully in anthropology, creating a system of measuring skulls.

Baer participated in expeditions to Novaia Zemlia (1837) and the Caspian Sea (1853-56). Their scientific results were a geographic description of the Caspian and the special series of publications on the geography of Russia edited by Baer and entitled Materials on Studying the Russian Empire and the Bordering Countries in Asia (vols. 1-26, 1839-72).

In 1857, Baer stated his proposition on the principles of the subsurface erosion of the right banks of rivers in the northern hemisphere and of the left banks in the southern hemisphere. He was one of the founders of the Russian Geographical Society. A cape on Novaia Zemlia and an island in the Taimyr Bay bear his name. His name is also used as a term denoting ridges in the Caspian Lowland.