498 



HADROSAURUS 



H^EMATURIA 



Iladrosaiirus, the name given to a very 

 large Dinosaurian (see DINOSAURIA) of the Creta- 

 ceous epoch, whose remains have been found in the 

 United States, especially in New Jersey. 



Haeckel, ERNST HEINRICH, a distinguished 

 German naturalist, born 16th February 1834, at 

 Potsdam. He studied natural science and medicine 

 at Wiirzburg, Berlin, and Vienna under Miiller, 

 Virchow, and Kolliker ; and soon became distin- 

 guished for his enthusiasm and originality in zoolo- 

 gical studies. After working for a while at Naples 

 and Messina, he became a privat-docent in the 

 university of Jena in 1861, a professor extra- 

 ordinarius in 1862, and an ordinary professor of 

 Zoology in 1865. In this position, in spite of other 

 inducements, Haeckel has remained working inde- 

 fatigably in his zoological institute, interrupted 

 only by visits to the North Sea shores and the 

 Mediterranean, or by more extended travels e.g. 

 to Madeira, the Canaries, Morocco, south Spain, 

 Arabia, India, and Ceylon. 



The most important of his numerous systematic 

 works are the following : a monograph on the 

 radiolarians ( Die Radiolarien, 1862), with a superb 

 atlas of 35 plates ; the classic work on calcareous 

 sponges (Die Kalkschwamme, 1872), important 

 both in relation to these animals and in its practical 

 illustration of general problems such as the nature 

 of species ; a yet larger work on jelly-lishes (System 

 der Medusen, 1879), with an atlas of 40 plates, 

 which like all Haeckel's work display inborn artistic 

 talent unsurpassed among naturalists ; several 

 smaller works, such as that on the development and 

 division of labour of the Siphonophora (1869), or 

 that on the Monera ( 1870), in which he ranks under 

 the title Protista the lowest forms of life which 

 have not taken a decisive step towards plants or 

 animals, or that on Arabian Corals (1876); and 

 finally his monumental contributions to the 

 Challenger Reports on Deep-sea Medusce (1882), 

 with 32 plates; on Siphonophora (1888), and 

 especially on Radiolaria ( 1887 ), in three volumes, 

 with 140 plates and 3500 new species. 



With the above gigantic descriptive work Haeckel 

 has combined two rarer accomplishments, successful 

 generalisation and popular exposition. His Gene- 

 relle Morphologic (2 vols. 1866), in its reasoned 

 orderliness and clear generalisations, ranks beside 

 Spencer's Principles of Biology ; it is not only one 

 or the very few works of moment on general mor- 

 phology, but is greater than its name suggests, 

 really including the gist of a series of treatises 

 e.g. on the commonly avoided subject of organic 

 stereometry the science of shape or promorpho- 

 logy, on the much-debated problem of individuality, 

 on the various modes of reproduction, on heredity, 

 and on the pedigrees of animals. Besides being 

 one of the first to sketch the genealogical tree 

 (Stammbaum) of animals, Haeckel gave precise and 

 luminous expression to the general fact that the 

 life-history of the individual' is a more or less accu- 

 rate recapitulation of its historic evolution. As a 

 special application of this ' fundamental biogenetic 

 law ' his Gastraea-theory ( elsewhere stated ) is of 

 paramount importance ( see EMBRYOLOGY ). Among 

 other general works may be noted his Periaenesis 

 of the JPlastidules ( 1876), an ingenious contribution 

 to the theory of Heredity (q.v.), and his specula- 

 tions on the origin and development of animal 

 tissues (1884). 



Apart from detailed zoological work, Haeckel has 

 devoted his life to applying trie doctrine of evolution 

 and to making it current coin. Owing much of his 

 motive to Darwin, he stood for a time almost alone 

 in Germany in his championship of a theory not 

 then popular. Before the publication of Darwin's 

 Descent of Man Haeckel was the only naturalist 

 who had clearly recognised the import of sexual 



selection, and of his Natural History of Creation 

 Darwin says, ' If this work had appeared before my 

 essay had been written, I should probably never 

 have completed it.' His most important exposi- 

 tory works are the above-mentioned Naturliche 

 Schppfungsgeschichte (1st ed. 1868; 8th ed. 1889), 

 which has been translated into twelve languages ; 

 'The Evolution of Man' (Anthropogenic, 1874; 3d 

 ed. 1877 ) ; and lectures on development and evolu- 

 tion, Gesammelte popular e Vortrage auf dem 

 Gebiete der Entwickelungslehre ( 1878-79 ). Haeckel ' 

 popular works are very brilliantly written, but they 

 are not always so careful in statement as Darwin's 

 classics, and offend many by their remorseless consist- 

 ency, and by their impatience with theological dogma 

 and teleological interpretation. He lias always 

 been set against compromise, defending the freedom 

 of science in a famous pamphlet (Freie Wissenscliaft 

 und Freie Lehre) written in answer to Virchow, 

 Other works are Die Medusen ( 1880) ; Darwin, 

 Goethe, und Lamarck (1882) ; Der Monismus ( 1892); 

 and Systematische Phylogenie ( 1894-95). 



Like all other naturalists, he has made a few 

 mistakes ; there are hints both in some of his draw- 

 ings and in some of his arguments of the dangers of 

 artistic and speculative imagination ; and it may be 

 doubted whether his early championship of evolu- 

 tion and Darwinism has not resulted in a taint of 

 dogmatism in what is sometimes called ' Haeckelis- 

 mus.' On the other hand, the thoroughness of his 

 systematic labours, the excellence of his draughts- 

 manship, the clear generalisations of his Generelle 

 Morphologie, the geniality of his teaching, and per- 

 haps above all the courage, lucidity, and eloquence 

 of his popular expository work on evolution have 

 raised Haeckel to a pre-eminent position among 

 modern naturalists. See BIOLOGY, DARWINIAN 

 THEORY, EMBRYOLOGY, EVOLUTION, HEREDITY, 

 ZOOLOGY. 



Haematemesis (Gr. haima, 'blood,' 

 ' vomiting ' ), the ejection of blood from the stomach 

 by vomiting. Its most common causes are gastric 

 ulcer ; congestion of the stomach or the neighbour- 

 ing portions of the alimentary canal (see STOMACH, 

 DISEASES OF) ; and certain conditions of the blood, 

 as in yellow fever, purpura, and sometimes in 

 typhus. See BLEEDING. 



Haematite ( Gr. haima, ' blood ' ), a mineral 

 consisting chiefly of peroxide of iron, is a valuable 

 iron ore. There are two principal varieties, Red 

 Haematite and Brown Haematite. See IRON. 



Haematocele (Gr. haima, 'blood,' and kele, 

 'tumour'), a tumour containing blood; opposed 

 to Hydrocele (q.v.). 



Haematoxylon. See LOGWOOD. 



IlU'lIia to/oil (Gr. haima, 'blood,' and zoon, 

 'an animal'), parasites occurring in the blood. 

 (a) Some Gregarinida (q.v.) live in the blood-cor- 

 puscles of frogs, reptiles, and birds. (b) A few 

 Nematodes occur in the vascular system e.g. Fil- 

 aria immitis, in the heart of the dog ; Strongyhis 

 armatus, causing abdominal aneurism, in horse and 

 ass ; Filaria sanguinis hominis, which in Australia, 

 China, India, Egypt, and Brazil occurs in man, 

 the sexual female in the lymph glands causing 

 Elephantiasis (q.v.), &c., the embryos circulating 

 in the blood and causing hsematuria, &c., while 

 the larval asexual stages occur within a mosquito. 

 (c) A very important blood parasite among Trema- 

 todes is Bilharzia (q.v.), occurring in Africa, in the 

 blood-vessels of the bladder, mesentery, and portal 

 system of man. See BILHARZIA, GREGARINIDA, 

 NEMATHELMIA, PARASITIC ANIMALS ; also Leuck- 

 art's Parasites of Man, trans, by Hoyle ( 1886). 



ll;rinut iiria (Gr. haima, 'blood,' and ouron, 

 'urine'), the discharge of blood with the urine, 

 usually from disease of the kidneys or bladder. It 



