Haeckel, Ernest Heinrich. — Biologist, born in Potsdam on 16 Feb. 1834, died in Jena on 9 Aug. 1919. He studied medicine in Würzburg and natural sciences in Vienna and Berlin. After numerous scientific expeditions, he spent 1859 and 1860 in Naples and Messina to study the fauna of the Mediterranean.
During this time he wrote Die Radiolarien, 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.; and also works of a general nature, which, translated into many languages, enjoyed 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 Gastraea-Theorie was published in Leipzig, a compendium and complement to his scientific-philosophical doctrine.
H. was one of the most eminent representatives of scientific materialism. A convinced Darwinian, he saw in biology the elucidation of evolution. From the monera, an amorphous mass of living matter, to man is an unbroken chain (monism), through stages temporarily represented in the embryonic development of each individual being. “Ontogeny is a recapitulation of phylogeny,” this is the “fundamental biogenetic law” already expressed by Serres and Müller and seen by the Italian Tommasi in the early period of his scientific activity (S. Tommasi, Istituzioni di fisiologia, Turin 1852).
Apart from the falsifications of which he was accused, the necessity of preconceived schemes and dogmatic rigor led H. to imagine and invent animal forms and types that never existed, so that, after the initial enthusiasm, his doctrine came to appear devoid of any critical spirit. He affirmed a priori that the second law of thermodynamics must be sacrificed because the constant increase in entropy would lead to the creation of the world, and thus contradict the first law. His “phylogenetic trees,” intended to show the historical connections between animal classes and types, according to a rigid monophyletism, were such that even Darwin, less imprudent, after admiring their originality, added: “your boldness sometimes makes me tremble.” At the Cambridge Congress (1898), to speak on the origin of man, he arranged on the stage the skeletons of anthropoid apes in an upright position, a contrivance he needed to suggest their near-bipedalism, whereas it is well known that higher primates, arboreal in habit, are quadrupedal on the ground. Similar contrivances served H. to suggest the similarity of human embryos to those of mammals, retouching and schematizing the figures. In this way H. forced the facts, thus entering into controversy with expert embryologists, among whom were W. His in earlier times and F. Keibel in later years.
Modern biology has now recognized that the problem of the beginning of evolution is as insoluble as that of the origin of life and that it is not possible to consider life as a simple consequence of random atomic aggregations and thought as a secretion of the brain, as H.’s materialism claimed.