FLUKE, or FLUKE-WORM. The popular name of various trematode worms. especially those which live endoparasitieally. The name liver fluke is especially applied to Distomum heputi runt, 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 les; than an inch in length. of an oval form, its breadth about half its length ; flat, in color like the liver in which it exists; it has no eyes nor other 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 short distance hack on the ventral surfaee. lint tit,: terminal seeker alone is perforated, and serves as a mouth, by which bile, the food of the erea.
Imre, is imbilwil; the t which proceeds from it does not, however, become a Calla 1, hilt 1111:11104 1100 two large 1l';1111•111,, ;11111 111 minute ramifications in all part, ; 1 he body. Large numbers of flukes are sim•tim•s found in the liver of a single sheep, and of very different siws, but they are now believed nut to multiply there a; was formerly supposed. Their egg,:, indeed, are produced there in great quan tity, lint find their way into the outer world to begin a series of transformations which are among the most extraordinary in the whole animal kingdom. The genus contains a great
number of speeies, infesting, in their mature state, different. kinds of animals, and finding their appropriate place in very different parts of the animal frame.
Instances have occurred of the presence of his/mania Inpat fru ni and two other species in the human liver and versa port c; hut their influence on the system is unknown; a species of much elongated form very in Egypt, infesting the versa port:e of man, and the walls of the urinary bladder. and producing and afterwards general disease; a small species (Disionium ophaulinobium I has heen found in the human eye, but probably through some such a•vident as in another ease has led to the occurrence of the common fluke under the skin of the foot, where it caused a sore, of all the known species, the Egyptian (Gymr cophorus Ir•matobium) is by far the most hurt ful, :Is infesting the human body. This species is also remarkably different from the others, in not being hermaphrodite, and in the extreme dis similarity of the male and female; the female being a threadlike worm, for wide]) a lodgment is provided in a furrow on the ventral surface of the male. See TRENIAT011.1.