TAPEWORM. The embryonic stages of tapeworm are hydatids (measles, cystioerci) or cysticcrcoidi. When a Ta-iiia ovium with miUiiie embryo is swallowed and reaches the human intestine, it migrates thiongli the blood-vessels or lymphatics into tlie tissues ;ind develoi)S into a hydatid. Both in man and in the pig tlieenibrj'o of Tania solium becomes a measle: while the embryo of Tania saginaia becomes, similarly, a measle in the cow. BLADDER WORMS OF PIG. a, Txnia solium (evaginated hGad);b, Taenia solium (in- vaginated head);c, Cysticercus cellulosse (head formation completed). If a cysticereus be ingested by a man, it de- velops in his intestine into a complete t^nia. In the human digestive tract a Cysticerciis cellulosw, or bladder worm, obtained from measly pork, be- comes a Twnia solium in six to ten weeks. The Tivnia canina develops in man from a cystieercoid of the cutaneous parasites of the dog. Twnia solium was so named by Linua>us because it is generally found alone; but in many instances two or three are found together, and in rare in- stances as many as 30 or 40 have been expelled from one patient. The full grown tsenia or strobila, is from 10 to 35 feet in length, and may consist of from 800 to 1000 proglottids. The sex- ually mature jiroglottids begin at about the four hundred and fiftieth segment. The breadth of the worm is about one-third of an inch at the widest. The head is very small and globular, or pear-shaped, is about the size of a small pinhead, and is dark with pigment. The crown of hooks numbers about 22 to 28 in each double row. The neck is very narrow and about one-half of an inch in length, and merges into the wider, seg- mented part. The impregnated eggs, when dis- charged into the intestine, do not mature there. They require the second host; such as, for ex- ample, the pig, who eats the expelled proglottids or the ova. The exception to this general rule is met when a cysticercus is foiuid together with a tapeworm in a human digestive tract. This is, necessarily, a source of grave danger, for the cysticercus may traverse the body as it does in the hog, and cause threatening or fatal condi- tions. Hence the imperative necessity of securing the expulsion of the entozoa as soon as their presence is known. When fully mature, the measle resembles a pea or a small kidney bean, being about one-third of an inch in diameter. Its great vesicular portion consists of a caudal extremity, inflated like a bladder, while the head, neck, and body may be drawn out in vermiform style. The great source of tapeworm is measly pork, eaten uncooked, or but partly cooked. The pre- ventive is to have pork, ham, bacon, and sau- sage always very thoroughly cooked. It ia also possible to ingest the embryo of the tape- worm with lettuce or other imcooked green food which has grown where a filthy stream flows over it, or which has been watered with liquid manure. 30 TAPEWOKM. Very scrupulous washing will prevent danger in these vegetables. Twnia saginata (or mediocancUata) has no circle of booklets and is about 25 feet in length. In its case, cattle instead of hogs constitute the intermediary hosts. It is transmitted through imperfectly cooked veal or beef. Twnia echino- coccus is, in its larval condition, probably more fatally injurious to the human race than all the other species of entozoa put together. In its mature (strobila) condition, in which it is found only in the dog and wolf, it seldom exceeds the fourth of an inch in length, and develops only four segments, including that of the head. The final segment, when sexually mature, equals in length the three anterior ones, and contains as many as 5000 eggs. The proscole.x or embryo forms large proliferous vesicles, in which the scolices or larvaj (known also as acephalocysts, echinococci, echinococcus heads or vesicles, pill- box hydatids, etc.) are developed by gemmation internally. The eggs develop in their interior a six-hooked embryo, and these embryos are intro- duced into our bodies with food or water into which the eggs have been carried. It finds its way into the liver, and later is carried by the blood current to other organs, including the lungs, the kidneys, the brain, and the bones. It grows slowly, many months elapsing after the ingestion of tapeworm eggs or embryos before the echinococci appear. In some countries in Europe hydatids are very prevalent. It is reported that the disease is endemic in Iceland to such an extent that one- sixth of the population suffer from it. The cause may be foimd in the great number of dogs harbored by the Icelanders. Twnia saginata is increasingly frequent in France, England, Italy, and Germany, as well as in Abyssinia, Senegam- bia, Algeria, and the Cape Colonies, Syria, Si- beria, the East Indies, and the Punjab. It is claimed by investigators that it (and not Twnia solium) is the common tapeworm in North America, as well as in Brazil, Peru, and the Argentine Republic. The presence of a tapeworm in the intestines may be suspected only from the occurrence of pieces of the entozoon in the dejecta, resembling fiat segments of macaroni. But in most cases it gives rise to a series of anomalous symptoms, including vertigo, noises in the ears, impairment of sight, itching of the nose and anus, salivation, dyspepsia, and loss of appetite, colic, pains over the epigastrium and in difTerent parts of the abdomen, palpitation, syncope, the sensation of weight in the abdomen, pains and lassitude in the limbs, and emaciation. In the treatment of taenia, prophylaxis is important. All meat must be so thoroughly cooked that the centre of each piece is subjected to great heat. Beef is the prin- cipal host of the entozoon. Rare beef must therefore be avoided. The medicinal treatment consists in causing the patient to fast for twen- ty-four hours and then administering the oleoresin of Filix vias (male fern), which must be followed by a brisk calomel purge. Santonin is also a reliable anthelmintic. The head must be sought in the excrement of the patient and medication must be repeated till the head is evacuated. Tapeworms, although rare among horses and cattle, are common in dogs and sheep, causing irritability of the bowels, and an unthrifty ap-
