BAER, KARL ERNST. – Estonian naturalist, b. at Piep in 1792, d. at Dorpat (Tartu) in 1876. After graduating in medicine at Dorpat, he went to Würzburg in 1815 to study anatomy at Döllinger’s school. In 1827 he was appointed professor of zoology at Königsberg, and from 1829 he taught zoology, anatomy, and physiology in St Petersburg for more than thirty years.
B.’s greatest fame embryology (v.). In this science he introduced the method of direct observation and comparison, adding the embryological criterion to the anatomo-comparative one in studies of the systematics and classification of animals (v.). He formulated the fundamental laws of development, elaborating the concept of progressive differentiation and upholding the epigenetic theory. In 1827 he discovered the ovum of mammals and described it in the Epistola de oxis mammalium et hominis genesi. He also studied the embryology of numerous invertebrates and termed the phenomena of larval parthenogenesis paedogenesis. His principal work on embryology is Untersuchungen über die Entwicklungsgeschichte der Thiere, Beobachtung und Reflexion (I, Königsberg 1827; II, ibid. 1837); numerous other works published in Müller's Archiv and elsewhere must be added to II. Important are B.’s contributions to anthropology (v.) ethnology (v.), published in Cronin selecta, in Vorlesungen über Anthropologie, etc. He discovered artificially deformed skulls in ancient burials in the Crimea; he made various comparative craniological observations and founded the German Society of Anthropology. B. also contributed greatly to the development of geographical knowledge, especially of Russia: among other things, he explored the Caspian basin, studied the bradyseismic phenomena of the Baltic coasts, and in 1837 undertook a long exploratory journey in the subarctic regions, advancing as far as Novaya Zemlya. From the observation that in the Siberian rivers flowing toward the Arctic Ocean the eastern bank is more eroded than the western, he derived the law of the deviation of rivers as a consequence of the Earth’s rotation. He founded the Geographical and Ethnological Society of St Petersburg and in 1835 began, with Helmersen, the publication of the Beiträge zur Kenntniss des russischen Reichs: there and in the bulletin of the Academy of Sciences of St Petersburg he published most of his geographical works. In his final work, Studien aus dem Gebiete der Naturwissenschaften (St Petersburg 1876), B. clarified his philosophical attitude toward the general problems of science, vigorously opposing materialist doctrines and the Haeckelian excesses of Darwinism, refuting the «biogenetic law» (v.), in support of which Haeckel had cited B.’s observations, and upholding, with arguments drawn from embryology, the teleological conception of life. Reading the works of E. E. Fichte led B., as he himself declared (Stölzle, pp. 419, 438), to modify in a theistic direction the pantheistic views to which he had previously been inclined.