HAECKEL. 436 Hj^IMOGLOBIN. schcngeschlechtes (1870) and Anthropogenie (1874) treat specially of the descent of man. In Die (Justrwatheorie (1874) he traces the phyletic iiistory of all the great groups of the animal kingdom, and finds for all of them a com- mon ancestor in the hypothetical gastr*a. (See Gastr.ea Theory.) Haeckel's influence upon con- temporaneous thought has been ver}' great. As a popular scicntilic writer and lecturer he has spread tlio Icnowiedge of the principles of Dar- winism throughout Germany and Europe, while his specuhilions on the phyletic history and an- cestry of the various groups of animals, and his attempts to classify them so as to express their relationships and common descent, although often erroneous, have stimulated investigation and led the way to the correct interpretation of phe- nomena. He is one of the best-known exponents of the monistic philosopliy. which he has ad- vocated in most of his speculative writings. His most important contriliution to it is Die WeU- riitsel. Gcincinverstiindliche Studien iibcr inoni- stischc I'liilosopliie (4th ed. 1900), which has been translated into English as The Riddle of the Universe (1902). In 1883 was published a popu- larly scientific account of a journey to the East Indies, translated into English under the title o; A Visit to Ceylon. The fourth German edition U entitled Insalijidc. H^MAMCEBA LAVERANT. See Spoeozoa. HJEMANTHUS, he-man'thus. See Blood- flower. H.iEMATEMESIS, hem'a-tem'e-sis (Neo-Lat., from Gk. o/un, hainia, blood + i/ieaig, emesis, vomiting, from i/uGh>, etnesin, to vomit) . Vomit- ing of blood. A symptom of ulcer or cancer of the stomach or of the oesophagus, hemorrhage from the lining of the stomach (as in alcoholism, poisoning, yellow fever, or purpura hjemor- rhagica), or cirrhosis of the liver. The blood may be fresh or clotted, mixed w'ith ingesta or with mucus. The treatment of this symptom is rest on the back, small pieces of ice swallowed, and absolute avoidance of solid and sometimes even liquid food, and of alcoholic drinks. It is a symptom of so much importance and gravitj' that the aid of a competent physician should be at once obtained wherever possible. H.ffiMATIN, hem'a-tTn (from Gk. alfia, haima, blood), CiJlaiNjFeOs, or, according to some chem- ists, C^jHjiN.FeO,. A bluish-black substance ob- tained, together with a proteid. when the oxy- htemoglobin of blood is treated with acids or alkalies, or is acted on by the gastric or pancre- atic juice. It is chemically very stable, the caustic alkalies, hydrochloric and nitric acids, having no effect on it. and it does not decom- pose even at as high a temperature as 180° C. It is insoluble in water and in the ordinary organic solvents, but dissolves readily in alkaline solutions. By the action of sulphuric acid it is transformed into hiemato-porphyrin, a substance that contains no iron and has also been obtained by decomposing chlorophyll (q.v.), the green coloring matter of plants. Pure hsematin may be prepared from ha^miii by boiling with noetic neid. washing Avith water, alcohol, and ether, dissolvinsr in dilute potash, and precipi- tating with hydrochloric acid: the lippmatin thus precipitated is carefully washed with hot water and dried at I.^O'-ISO'C. Hipmatin may also be obtained directly from blood, the following being a convenient method of preparation : delibrinated blood is mixed to a thin paste with potassium carbonate, the paste is evaporated to dryness on a water-bath, and the residue is extracted with boiling alcohol; the solution thus obtained is made acid by carefully adding sulphuric acid, is filtered, again made alkaline by adding an excess of ammonia, and then evaporated to dryness ; on washing the residue with boiling water and dic- ing at 130°-150° C, a fairly good specimen of ha'iiiatin is obtained. H.a;MAT'OCELE (from Gk. a(/ia, haima, blood + Ki/'/r/. I;clc, tumor). A tumor containing blood. HiEMATOXYLIN, hem'a-toks'i-lin (from Gk. 07/0, /laimu, blood + ^v'Aov, xylon, wood) . A chromogen (a term u.sed by "chemists to denote certain nearly or quite colorless substances whicii, under certain influences, yield well-marked colors) obtained by extracting logwood {Hama- toxylon cumpcnehianum) with ether. Its com- position is represented by the formula CuHnOj. 3H3O. and in its pure state it occurs in trans- parent glistening straw-colored prisms. It has a sweet and not astringent taste, is sparingly sol- uble in cold water, but dissolves readily in boil- ing water, alcohol, and ether. The aqueous solu- tion is not affected by the air, but if a very small quantity of ammonia is added, it assumes an intense reddish purple color. This color is due to a decomposition, of which a substance SoHi^O,;, termed Itcrmatein, is one of the products. The compound resulting from the union of harnatein and ammonia is represented by the formula C„H,,0„NHj. Ha^niatoxylin is used in the arts for producing blue and black colors. The commercial liwmein is an impure form of hoematoxylin. Log- wood (q.v.) contains about 12 per cent, of ha^ma- toxj'lin. H:.ffiM'ATOZO'A. See Sporozoa. H^M'ATU'RIA (Neo-Lat.. from Gk. nifia. haima. blood --'oiftov, ourmi, urine). The appear- ance of blood in the xirine. It is a symptom of disease of the kidneys, bladder, or prostate gland (tumor, stone, tubercle, syphilis, hypertrophy, etc.) in most cases. The treatment depends upon the condition present. Eest is important. HLffi'MODYN'AMOM'ETER (from Gk. a)ua, haima. blood + r'Ora/Liir. di/iiamix. power + /itrpnv, metron, measure). An instrument for determin- ing the pressure of the blood in the arteries and veins of the living body. The pressure of the blood is measured, as in the barometer, by the column of mercury that it balances. The instru- ment has been improved in various ways, and a contrivance added by which the oscillations of the mercury are inscribed in the form of an un- dulating curve on a cylinder made to revolve by clockwork. Recently instruments have been in- troduced by means of which the blood-pressure can be determined in the human subject with facility and precision; these are of great clinical value. See Spiivr.MOOE.iPn. H.a;'MOGLO'BIN (from Ok. o'//'". haima, blood + Lat. qlohiis. ball). An important sub- stance found in red blood-corpuscles, and hav- ing the property of readily taking up oxygen from the air. and just as readily giving it up to the tissues of the body. The chemical na- ture of hoemoglobin is as yet little understood, and even its true chemical composition is un-
