FLUGGE. 765 FLUORESCENCE. 1878 until 18s:;, when he was called to the chair of hygiene at the Hygienic institute in GSttin in issT be was called to a similar position al Breslau. His original researches in the depart rcents of experiments I hj giene and bai I have found wide recognition. In the well known work entitled Beitrdge zur Hygiene (1872), he discusses house sanitation, porosity, and defile ment of the soil, and the t I distributed in charitable institutions and hospitals. His other works include Die Mikroorganismen (3d ed, L896), and Qrundriss der Eygiem (4th ed. 1894). In collaboration with Koch, the cele brated bacteriologist, he became an editor of the Zeitschrift fiir Hygiene in 1886. FLUGGEN, flu'gen, Gisbebt (1811-59). A German genre painter, limn al Cologne. lie studied al (lie Academy of DUsseldorf, and then settled in Munich in 1835. He painted in the manner of Wilkie, and is often called 'Hie Ger- man Wiikie.' His work abounds in eighteenth century sentimentalities. His best pictures are: "Servants Surprised" (1839); "The Chess Plaj ers;" "The Interrupted Marriage Contract;" and an historical painting, "The Last .Minnies of thu King Frederick Augustus 1 1, of Saxony." His son, Joseph (1842 — ), genre and historical painter, was born in Munich, and studied at the academy there. His works include "The Flight 'if Hie Landgravine' Elizabeth" ( ISt',7 ) , and "The Daugh- ter of the Hostess" (1869). FLUID (Lat. fluidus, flowing, from fluere, to flow, Gk. (pMetv, phlyein, to overflow). A gen- eral name applied to liquids and gases. Fluids readily assume the form of the vessel in which they are contained, an exceedingly small force being sufficient to change the relative position of their molecules. Gases are compressible or elas- tic fluids, their volume depending on the pressure exerted upon them. Liquids are relatively in- compressible. The term fluids has also been ap- plied to hypothetical substances which were sup- posed to cause the phenomena of heat, magnet- ism, and electricity. The luminiferous ether, in which, according to modern science, the waxes of light, electricity, and radiant heat are propa- gated, is also sometimes referred to as a fluid. See Elasticity; Hydrostatics; Matter, section Properties of Matter; Cbiticax Point; etc. FLUKE (AS. floe, flat fish, Icel. floki, kind of halibut). In ichthyology, a name applied, more commonly in Great Britain than in the United States, to various species of flounders (q.V.). A familiar example is the Scotch bonnet-fluke or brill (Rhombus Icevis). FLUKE, or Fluke-Worm. The popular name of various trematode worms, especially those which live endoparasiticallv. The name liver- fluke is especially applied to Dish, muni hepati- cum, which is common in the liver and biliary duets of ruminants, particularly of sheep, in which it produces the disease called rot, often causing great mortality in flocks during wet sea sons and on ill -drained lands. It is generally less f ban an inch in length, of an oval form, its breadth about half its length: Hat, in color like the liver in which it exists; it has no eyes nor otber known organs of special sense; it is hermaphrodite, and the organs of reproduction occupy a great part of its body; its anterior extremity is furnished with a sucker, and another is situated at a on the ventral ul th- terminal uckcr alone is pen.,. ■' B ' ■ Which bile. Hie .1 ol ll . tine, i- imbibed; the tube which pr icda from il does ui , er, become a proper inti canal, but soon divide into 1 o lui inches, and ends in minute ramifical ion ■ in all pai the body. Large numbers of Dukes are son i fOUnd 111 Hie li, i ad .,1 . I V different tzi but I b.i are aovi believed multiply there a wa formerly supposed. Their eggs, indeed, an- produced there in great quan- tity, Imt find their way i i utcr world to begin a -.1 ie ol trait foi mat ions whii an g the mo I dinary in the whole animal kingdom. 'I I ntaii number of pecies, ting in i heir mature Btate, different I inds of animals, and finding their appropriate place in very different pan- of the annual frame. instances have occurred of tin- presence of Distomum hepaticum and two other species in the human liver ami vena porta-: i.ni their influence on the system i- unknown; a speeii ol much elongated form [Oyncecophorus /mi,,... i ; i j common in Egypt, infesting the vena porta of man. and the walls of Hie urinary bladder, and producing local, and afterwards general diseasi a -mall species [Distomum ophthalmobium) )i.<~ been found in Hie human eye but probably 1 I [h - e such accident a- in anot her ea-c has led to th currence of the common fluke under the -km of the fool, where it caused I • if all (he known spnie-. tlie Egyptian [Oyna cophorus haematobium) i- by fai Hie mosl hurt- ful, as infesting the human body. This species i- also remarkably different from the oilier-, in mi being hermaphrodite, and in the extrci lis- similarity of the male and female; the being a thread like worm, for which a lodgment i provided in a furrow on the ventral surface of the male. See TrEMATODA. FLUME (from OF. fium, river, from T.at. flumen, stream, from fluere, to Bow). An artifi- cial channel used to convey water for power de- velopment, hydraulic mining, and irrigation. It is most commonly of wood, but may I f steel. It i- place, i above ground; often on trestles or other elevated supports to keep it. in a nearly level position. See IRRIGATION. FLU'ORES'CENCE (cf. Fr. fluorescence, Sp., Port, fluorescencia, from Lai. fluor, flux, from fluere, to flow). When ether waves are absorbed by a body which they have entered, their energy, as ii rule is distributed throughout the minute particles of the body, and some leu effect i- pro- duced, generally rise in temperature. A- a result of this the body will now radiate n, than before, and in so doing will give out waves in the ether which are called heat wave-, i.e. their wave-length is long. Thus, a piece of red glass absorbs certain ether waves, among them all the visible ones except those which combine to pro- duce the sensation red in t 1 ,,, human eyre The temperature of the glass rises, and it emits ether waxes which are too long to affect the sense of sight. There are many bodies, however, in which the energy of the absorbed wave- is not -pent in producing rise in temperature, and the con- quent en issii n of long heat waves, but i- in producing the emission of ether-waves which
