HAECKEL 



3772 



Hadrian's Wall. Map indicating the course of the Roman wall and the 

 stationary camps established to defend the northern frontier of Britain 



and G ft. to 9| ft. thick, flanked 

 by a ditch averaging 36ft. by 15 ft. 

 A military road ran more or less 

 parallel on the S. side, with an outer 

 ditch and earthen mound the 

 vallum. At intervals of a Roman 

 mile were about 80 smaller castella 

 or milecastles, averaging 60 ft. by 

 70 ft., whereof f>2 are traceable. 

 Between them were 320 recessed 

 watchtowers. See Britain. 



Haeckel, ERNST HEiNRiCH(1834 

 -1919). German scientist. Born at 

 Potsdam, Feb. 16, 1834, he studied 

 medicine at Wiirzburg, Berlin, and 

 Vienna. For a short time he prac- 

 tised as a physician, but devoting 

 himself to natural history became 

 professor of comparative -anatomy 

 and director of the zoological in- 

 stitute at Jena, in 1862. Three 

 years later he was appointed pro- 

 fessor of zoology, and he remained 

 at Jena for the rest of his life. 



On the publication of Darwin's 

 Origin of Species, Haeckel at once 

 became an enthusiastic convert to 

 the Darwinian theory of evolution. 

 In his Natural History of Creation, 

 1 868, he traced the descent of man 

 from protoplasm to the chimpanzee 

 in 26 stages, and declared human 

 remains found in Java to be the 

 missing link be- 

 tween man 

 and the man- 

 like apes. 



With Darwin, 

 he maintained 

 the hereditary 

 transmission of 

 acquired char- 

 acters, against 



the 



iews of Weismann and later 

 biologists, arid held that the most 

 elementary forms of substance, 

 matter, and ether possessed sensa- 

 tion and will. His other books, 

 General Morphology of Organisms, 

 1866; The Last Link, 1898; and 

 The Riddle of the Universe, 1901, 

 all expositions of evolution, have 

 been translated into many lan- 

 guages, and the last-named is ac- 

 cepted as a popular text-book of 

 rationalism. In it Haeckel claimed 

 to have demonstrated by his theory 

 of monism the non-existence of a 



personal God, of free will, and of 

 the soul of man after death. In 

 Oct., 1914, he signed the letter of the 

 German scientists declaring Ger- 

 many to be tree of anv blame for the 

 outbreak of the Great War. He died 



Hadrian's Wall. Fart of the wall near Haydon Bridge, 

 7 miles west of Corbridge, Northumberland 



at Jena, Aug. 8, 1919. See Evolu- 

 tion; Pithecanthropus erecius. 



Haelen. Village of Belgium. 

 In the prov. of Limburg, it is 11 m. 

 W. of Hasselt. It was the scene of 

 a sharp engagement between the 

 Belgians and Germans on Aug. 12, 

 1914. The action, which lasted 5 

 hours, took place among cornfields, 

 and a charge of Belgian cavalry 

 completed the rout of the enemy, 

 who had made an attack here to 

 force the passage of the Gette. See 

 Belgium, Occupation of. 



Haematite (Greek haimatetes, 

 blood -like). Ore of iron, so named 

 from its red, metallic lustre. It 

 usually occurs in kidney-shaped, 

 granular or amorphous masses. 

 Most red rocks contain haematite. 

 Specular iron ore is the crystallised 

 variety of the mineral, and is steel- 

 grey in colour. Red ochre is an 

 earthy, impure form of haematite. 

 In one form or another the mineral 

 is found in most parts of the world. 

 The finest variety of specular iron 

 ore comes from Elba. 



The mineral is put to a large 

 number of uses. Finely ground it is 

 a basis for paints ; pencils made 

 from it are used by masons for 

 marking stone ; powdered, it is 

 extensively used for polishing pur- 

 poses, particularly for polishing 

 gold and silver ; cut and polished 

 as an ornamental stone; it is also 



HAEMORRHAGE 



used in the manufacture of Besse- 

 mer steel. See Iron. 



Haematoxylin. Colourless cry- 

 stalline compound present in 

 freshly chipped logwood (Haemat- 

 oxylon campechianum). It is con- 

 verted into the colouring matter 

 haematein, naturally in the wood, 

 on lengthy exposure to the air, and 

 artificially by the addition of an 

 alkali. Haematoxylin is prepared 

 by combining fresh logwood ex- 

 tract with ether. It is employed in 

 cotton dyeing. 



Haemoglobin (Gr. haima, 

 blood; Lat. globus, ball). The 

 colouring matter of the blood. In 

 bright red arterial blood it is 

 , loosely combined 

 ] with oxygen, form- 

 I ing oxy-haemoglo- 

 I bin. During the 

 ; circulation of the 

 blood, the body tis- 

 sues abstract the 

 oxygen, and leave 

 the colouring mat- 

 teras haemoglobin. 

 See Blood. 



Haemophilia 

 (Gr. haima, blood; 

 philia, friendship, 

 tendency to). Con- 

 genital tendency to 

 bleeding even from 

 quite trivial 

 wounds. The con- 

 dition is strongly hereditary, and is 

 transmitted only through the fe- 

 male line. Haemophilia is generally 

 recognized during the first year of 

 life, owing to almost uncontrollable 

 haemorrhage from a trifling cut. 

 Besides bleeding from a wound, 

 there may be serious spontaneous 

 haemorrhages from the nose, 

 mouth, stomach, and bowels. If 

 wounded, the patient should be kept 

 absolutely at rest, and the bleeding 

 controlled by pressure and the 

 application of ice, or drugs which 

 hasten the coagulation of blood. 



Haemoptysis (Gr. haima, blood; 

 ptysis, spitting). Bleeding from the 

 larynx, trachaea, or lungs. 



Haemorrhage (Gr. haimor- 

 rhagia, bloody flux). Internal or 

 external discharge of blood from 

 a blood-vessel. Internal haemor- 

 rhage, when the bleeding occurs 

 into the cavity of the chest or 

 abdomen, may be recognized by 

 the onset of faintness, pallor, air- 

 hunger, failing pulse, and finally 

 collapse. The patient should be 

 laid flat, fresh air provided, ice 

 given to suck, and cold dressings, 

 preferably in the form of ice, 

 applied to the seat of the haemor- 

 rhage if known. If collapse occurs, 

 the limbs should be raised and band- 

 aged firmly from end to end. No 

 stimulant should be given, as this 

 tends to cause a continuance of the 



