LENIA. A ttenia consists of a scolex, or head, and detachable segments, or proglottids. Within the scolex is the brain; on the outer surface of the scolex are four sucking disks as well as a ring of hooks. Fixation is secured through the suckers and hooks. In each proglottid is an albumin gland; and a uterus and a vas deferens end in openings on the side of the proglottid. New proglottids grow behind the head, by di vision of its posterior part. The farther from the head, the larger is the proglottid. The distal proglottids separate from time to time and are excreted with the frees of the host. But the head must be removed to secure freedom from the parasite.
The embryonic stages of tapeworm are hydatids (measles, eysticerei) or eystieercoidi. When a Twnia orium with mature embryo is swallowed and reaches the human intestine, it migrates through the blood-vessels or lymphatics into the tissues and develops into a hydatid. Both in man and in the pig tie embryo of becomes a measles while the embryo of Tannin sayinata becomes, similarly. a measle in the cow-.
If a cysticercus be ingested by a man, it de velops in his intestine into a complete txrda. In the human digestive tract a Cysti-cercus collulosw, or bladder W01111, obtained from measly pork, be comes a Twnia solium in six to ten weeks. The Twnia canina develops in mall from a cystieercoid of the cutaneous parasites of the dog. Twnia solium was so named by Linnams 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 tnia or strobila is from I0 to 35 feet in length, and may consist of from S00 to 1000 proglottids. The sex ually mature proglottids begin at about the fora• 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 cystice•cus is found 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 o• fatal condi tions. Hence the impe•ative 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 candid 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 is also possible to ingest the embryo of the tape worm with lettuce or other uncooked green food which has grown where a filthy stream flows over it, or which has been watered with liquid manure.
Very scrupulous washing will prevent danger in these vegetables.
Tcenia sayinata (o• mcdiocnncllata) has no circle of hooklets and is about 25 feet in length.
case, cattle instead of hogs constitute the intermediary hosts. It is transmitted through imperfectly cooked veal or beef. Tapia cchino 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 clog 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 proseolex or embryo forms large proliferous vesicles, in which the scolices or larva: (known also as acephalocysts, echinocoeci, echinococcus heads or vesicles, pill box hydatids, etc.) are developed by gemination 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 echinocoeci appear.