HAECKEL, ERNEST HEINRICH. — Biologist, born in Potsdam on 16 February 1834, died in Jena on 9 August 1919. He studied medicine at Würzburg and natural sciences at Vienna and Berlin. After numerous scientific journeys, he spent 1859 and 1860 in Naples and Messina studying the fauna of the Mediterranean.
During this period he wrote Die Radiolaria, eine Monographie (Berlin 1862), which earned him the chair of zoology at Jena. In the following years he published numerous scientific works, including Beiträge zur Naturgeschichte der Hydromedusen (Leipzig 1865); Zur Entwicklungsgeschichte der Syphonophoren (Utrecht 1869); Das System der Medusen (Jena 1879), etc.; as well as works of a general nature which, translated into many languages, achieved wide circulation: Generelle Morphologie der Organismen (Berlin 1866); Natürliche Schöpfungsgeschichte (ibid. 1868), translated
into Italian by D. Rosa (Turin 1892), etc. In 1877 his Studien zur Gastrea-Theorie was published in Leipzig, a compendium and supplement to his scientific-philosophical doctrine.
H. was one of the most eminent representatives of scientific materialism. A convinced Darwinist, he saw in embryology the clarification of evolution. From the monera, an amorphous mass of living matter, to man there is an unbroken chain (monism), through stages that are temporarily represented in the embryological development of each individual being. “Ontogeny is a recapitulation of phylogeny”: this is the “fundamental biogenetic law” already expressed by Serres and Müller and recognized by the Italian Tommasi in the first period of his scientific activity (S. Tommasi, Istituzioni di fisiologia, Turin 1852).
Quite apart from the falsifications of which he was accused, the necessity of the predetermined schemes and the dogmatic rigor led H. to imagine and invent forms and types of animals that had never existed, so that, after its initial enthusiasm, his doctrine ultimately appeared devoid of any critical spirit. He asserted a priori that the second law of thermodynamics had to be sacrificed because the constant increase of entropy would lead to the creation of the world and thus contradict the first law. His “phylogenetic trees,” intended to show the historical connections among animal classes and types according to a rigid monophyletism, were such that Darwin himself, less imprudent, after admiring their originality, added: “your audacity sometimes makes me tremble.” At the Cambridge Congress (1898), in order to speak on the origin of man, he arranged on the stage the skeletons of anthropoid apes in an upright position, an artifice that he needed in order to suggest their almost bipedal character, whereas it is well known that the higher, arboreal primates are quadrupeds on the ground. Similar artifices served H. to suggest the resemblance of human embryos to those of mammals, by retouching and schematizing the figures. In this way H. forced the facts, consequently entering into controversy with expert embryologists, among them W. His in the early period and F. Keibel in the later one.
Modern biology has by now recognized that the problem of the beginning of evolution is just as insoluble as that of the origin of life, and that it is impossible to regard life as the simple consequence of chance atomic aggregations and thought as a secretion of the brain, as H.’s materialism maintained.