Tapeworm
2 of the 7 encyclopedias on this shelf carry an entry for Tapeworm. Both are reproduced below, so you can see where they agree and where they differ.
Collier's New Encyclopedia (1921)
an Tænia solium, in form somewhat resembling tape. Its length is from 5 to 15 yards, and its breadth from two lines at the narrowest part to four or five at the other or broader extremity. At the narrow end is the head, which is terminated B A TAPEWORM. A AND B-HEAD ENLARGED anteriorly by a central rostellum, surrounded by a crown of small recurved hooks, and behind them four suctorial depressions; then follow an immense number of segments, each full of microscopic ova. The segments are capable of being detached when mature, and reproducing the parasite. There is no mouth; but nutrition appears to take place through the tissues of the animal, as algæ derive nourishment from the sea water in which they float. The digestive system consists of two tubes or lateral canals, extending from the anterior to the posterior end of the body, and a transverse canal at the summit of each joint. The tapeworm lives in the small intestines of man, affixing itself by its double circle of hooks. When the reproductive joints or proglottides become mature, they break off and are voided with the stools. They may get into water, or may be blown about with the wind, till some of them are at length swallowed by the pig, and produce a parasite called Cysticercus cellulosæ, which causes measles in the pig. When the measly pork is eaten by man, a tapeworm, the ordinary T. solium, appears in his intestines. This species mainly affects the poor, who are the chief pork-eaters. Called more fully the pork tapeworm. The beef tapeworm, T. mediocanellata, has no coronet of hooks on the head. The segments are somewhat larger than in the ordinary tapeworm. It is 15 to 23 feet long. The cysticercus of this species forms measles in the ox, and is swallowed by man in eating beef. It chiefly affects the rich. The broad tapeworm, Bothriocephalus latus, is 25 feet long by nearly an inch broad, and chiefly affects the inhabitants of Switzerland, Russia and Poland. The adult sexual Tæniadæ live for the most part in birds and mammals, the larval "bladder worms" or Cysticerci occur in both higher and lower animals. Two Tæniadæ are in the adult sexual state parasitic in man: Tænia solium, with the bladder worm stage in the pig; T. saginate or mediocanellata, with bladder worm in the ox; and some others, T. cucumerina, T. nana, T. flavomaculata, and T. madagascariensis, occasionally occur. They infest the small intestine, and there also Bothriocephalus latus (larval in pike and burbot) may be found. Moreover tænioid bladder worms also occur in man, the most important being that of T. echinococcus, which lives as an adult tapeworm in the dog. The presence of tapeworm in the small intestine need not be dangerous, but it is usually troublesome, giving rise to disturbances of digestion, colic-like pains, diarrhea, or, on the contrary, constipation, besides less local effects, such as anæmic and neurotic states. Of anthelmintics-which are intended to expel the parasite from the intestine-there is no lack in the pharmacopœia.
Aiton's Encyclopedia (1910)
a parasitic flat-worm. The common tapeworms live in the intestines of man. One end is attached to the wall, the other hangs free. The tapeworm has no mouth, no alimentary canal . It lives by absorbing the digested food of its host. It has no eyes, no special sense of any kind. It attains an extreme length of several yards. The body consists of some several hundred segments, according to age and favorable conditions. There are several species. The larvae of the species, known as the beef tapeworm, the pork tapeworm, and the broad tapeworm, are derived from beef, pork, and the flesh of fishes respectively. The head, or the part by which the animal attaches itself by means of hooks to the wall of the human intestine, is really the whole animal. The segments are merely successive egg cases, the oldest being farthest from the head. A chain of them may break off at any time, leaving the worm uninjured. It is necessary to detach the head before the tapeworm can be expelled from the body. In fact, the breaking away of segments is nature's plan. The egg sacs must be expelled and be eaten with the food by some other animal, as an ox, hog, or fish, in the intestine of which the larvae develop before they are ready to enter man. Two entirely different animals are requisite, therefore, as homes for the tapeworm. See Parasite