CESTODES, OR TAPEWORMS Taivia solium, the armed tapeworm. —This attains a length of six to nine feet. On the small head, which reaches the size of a pin-head, are four slickers and a powerful rostellum, armed with twenty five or thirty hooks (Fig. 45). Tiehind the neck, which is only one eentinictre long, come a long series of segments, three feet in length, becoming gradually squarer ; behind these, the sexually mature segments. The latter are 9 to 10 nun. long and 6 to 7 broad.* The uterus, which is packed full of eggs, shows on each side eight to ten dendrically branched arms, or twigs (Fig. 46). The ripe proglot tides are passed in part singly, and in part with several hanging to gether. The eggs (Fig. 47) are round, and have a diameter of .03 nan.
The external coat consists of delicate, radiating brownish rods, which give the appearance of a fine mosaic, under a high power (Fig. 47, O. On soction of the egg, we see the embryo fitted out with hooklets within the lining membrane (Fig. 47, b).
Eating pork that contains living cysts gives rise to this disease in man. The eysticercus celluloste presents a small vesicle, which may reach the size of a hemp-seed; and, besides a small amount of albumin ous fluid, contains the completely developed head of the Taqtia solium. Swine acquire the measles by eating the proglottides, or eggs of the parasite; these animals at pasture, having plentiful opportunity to take in human excrement in meadows, woods, streets, or roads, are affected with this disease in a good deal higher proportion than are swine kept in stalls. Man can also take in the cycticercus of the tinnia solium, anti this is usually due to lack of cleanliness. The insane frequently infect themselves, or the infection may come from other persons.
The course of eysticercosis, which is encountered with extreme rarity in man, is more or less latent, according to the locality attacked, the function of the organ involved and the number of migratory embr.-os, but it may give rise to very severe symptoms when it attacks the eye ground, the brain, or the spinal cord.
2. neniasaginata, mediocanellata fat worm) attains a length of eighteen to twenty-four feet, and even over. The head often more than 2 mm. thick, of cubic form, usually shows a marked brownish to blackish pigmentation, it has neit her rostellum nor hooks, but has four powerfully developed suckers (Fig. 481. The sexually mature proglottides (Fig. 491 are 16 to 20 mm. long and 7 to 8 mm. broad. The uterus has on each side twenty to twenty-five delicate lateral branches, which branch dichotomously. Most of the proglottides, which are discharged singly, contain few eggs. These eggs differ from those of the Ttcnia solium in their smaller size. This, however, is not constant. The statetnent that the eggs of the Tinnia saginata have no hooklets is an error. The embryos of both tieni are armed. The
infection of man with the Tamia saginata comes from eating measled meat. The cattle reinfect themselves through contact in the meadows with a species of Tamia saginata derived from man, or with their eggs, containing embryos.
3. Bothrioreplat/us lulus (the broad worm) is named from the dimpled depression found at the sides of the wedge-shaped head (Fig. 50). It is the largest human parasite, attaining a length of thirty feet and over.
The ripe proglottides are only 5 to 6 um). long and 12 to 15 mm. broad, and have in their centre a rosette-like marking, which represents the uterus packed with eggs (Fig. 51). Long sections of the proglottides are often passed with the stools in a macerated condition. The eggs are plentiful in the feees. They are .07 min. long to .015 nun. broad, and yellow to brownish in color; and have a cap-like closure at one pole (Fig. 52). The escaping embryo, which has six books (called oneo sphere), is decorated over the whole body with delieate cilia. It swims actively in water; and finally, either directly or through an intermediary host, enters certain varieties of fish (pike, perch, quab, and salmon), in which it becomes encysted. By eating such fish or their products (such as caviare), man becomes infected, if the cysts have not been destroyed. Bothriocephalus disease is, therefore, to be found most frequently at the sca-shore and on the ocean. Of late years, however, the frequency with which such disease is encountered inland has increased considerably. 1. Tcenia cuctinierina (elliptica), the dog oz. cat tapeworm, becomes ten to thirty elm long. The head has a powerful rostellum, with sixty hooks, arranged in four rows; and four suckers (Fig. 53). The ripe proglottides (Fig. 5-1) are S to 10 nun. long and 2 to 21 mm. broad, and have a gray or reddish color—due to the shilling through of the cocoon, which contains 6, 8, or 12 eggs (Fig. 55). The single egg ures .05 mm. in diameter, and contains an embryo with six hooks. These enbryos become encysted in dogs', as well as in human fleas—Pulex serraticeps and Pulex irritans and in dog's lice (triehodectcs canis). Since dogs and cats fight their vermin by biting and pinching, or by licking their body, they swallow the intermediary host and infect selves with the cystieercoids, which are again conveyed to children that are in the habit of playing with these animals; and it is a most striking fact that, Up to the present time, the only case-reports of this diseasc have concerned the presence of these parasites in children. From an observation of Kohl, about three weeks are required after the cysticer cold enters the body before ripe proglottides are passed. Asam-Huber have carefully studied the literature concerning these parasites.